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  1. #1
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  2. #2
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    Default More info & questions answered.

    In your conversion truck, how did you get the climate controls and radio to work, I know that your conversion guide mentions that it includes information to produce a running and drivable truck. So, are there any manuals or wiring diagrams for those kind of things in the truck? Also what kind of unforeseen problems further down the road have you run into? Any electrical or drive train problems or other little things? Any help is very appreciated thank you-Robert


    I installed the complete under dash/inside cab wiring harness, fuse block, and electrical junction blocks matching the engine/trans package. I also installed a matching dash. This allowed me to use the matching audio system, light switch, pushbutton 4WD switch and instrument panel gauge cluster. I retained the original 1989 control panel for the HVAC system by interfacing it with the new harness. This is covered in the Conversion Guide (HVAC system).

    No problems with the drivetrain have come up, except that if doing it again, I would install a matching model year steering column, which would simplify the conversion. The Guide shows how to retain the original steering column and get the cruise, turn, horn and wiper system integrated into the new electrical system.

    Jim

    For this conversion, how much would the approximate cost be? I've read all the articles I can find on the conversion you did with the '89 however I can’t find a build cost. I'm looking to do it to my 1996 and was wondering about an approximate build cost to just get it running and drivable. Thank you -Robert


    Assuming you did all the work, the total cost would depend on what you pay for a conversion package. I've heard of packages going for $5k to $12k. Many almost-new low mileage salvage trucks go for somewhere in the $7500 range, but you'd need a salvage license to bid on insurance vehicles. Ebay can also be a good source for engines and parts.

    Jim

    You mentioned a conversion kit, aside from taking the parts out if a salvage truck what do you mean?
    Thank you Robert
    I referred to a conversion parts package that was assembled from a salvage truck. A package will contain the complete engine/transmission, all related wiring harnesses, computer modules, fuse blocks, electrical center, intercooler/hoses, radiator, steering column, etc.

    There have been a few "packages" sold on eBay. I urge people to buy a complete package or a complete salvage truck. The little bits & pieces can really run the cost up if you have to buy them over the counter.

    Jim

  3. #3

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    Now I started connecting inside wires and bad thing is, that my junction block does not match with Jim´s one and if I checked the ALLDATA, then that one there didnt match with mine nor Jim´s.
    http://stuff.e30club.org/images/suburban/juncblock.JPG
    So I just have to pull out all fuses and put them in one-by-one to see, where I need to connect the right wire or someone has a better solution?

  4. #4
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    I bought the full set of GM manuals and the separate electrical diagram book for the model year of the engine package I used. In these books was an illustration and pinout descriptions for the junction block I used. If buying the books isn't a possibility, I'd visit a a local dealership and try to get a printout from them for your junction block.

    By the way, the separate electrical diagram book isn't strictly necessary because the individual diagrams can be found scattered throughout the service manual book set. Being scattered makes it more time consuming to get all of the information, so I found it better to have all of the diagrams in one book. I recommend getting the GM electrical diagram book matching the model year of your engine package.

    By the way, please don't post scans of diagrams or other copyrighted material from AllData or any other source.

    Jim

  5. #5

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    As Im building a car in Norway, then in this country, it isnt possible to buy this book, they just dont sell it. Although I purchased all possible versions in alldata, that my donor car could be. It turned out, its a 2003 year model. I noticed, that every year has its own junction block under the dashboard, so now its pretty easy to find out everything. And it was true, that it needs a feeding pump, because before there was problems with starting the car. If it started, then it ran just well. After intsalling a Holley performance feeding pump, it starts just nicely and runs like a sportscar

    But does anyone know, what to do with the brake fluid level indicator? As my suburban tank does not have such plug, then i just leave it there hanging? Actually I dont like the light in the dashboard, that says, you have too little brake fluid. And as handbrake uses the same light, I just cant disable it.

  6. #6
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    Arrow

    The brake fluid level indicator sensor is a normally open circuit, closed when the fluid level is sufficient. You should be able to shunt the connector to get the lamp to go out. If you do this and the lamp stays on, then you have another sensor or switch in the system that's not happy, or missing, or the brake fluid level harness is not wired correctly into the system. The EBCM (Electronic Brake Control Module) receives the input from the brake fluid level switch, and controls the IP lamp. If you pacify all the switches/sensors, and still have the lamp on, I'd suspect an issue with the EBCM, or a weak/missing ground in the circuit. If you haven't installed the late model EBCM, that could very well be the problem, with the BCM missing the input, or the input is not correct from the park brake switch (which is monitored by the BCM)
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  7. #7

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    Im doing conversion on a 1995 Suburban. Donor car is 2001 Silverado. I have the book "Duramax 6600 Conversions&Repower Projects"

    My Suburban does not have an HVAC like in the book, I took all the wiring out behind dashboard (I want to keep the old dashboard), that included all heater wiring as well. Do I just have to compare two car wiring diagrams and search for right wires to connect to heater plugs?
    I only left the wires, that came out from drivers door and went behind dashboard to passenger door. How did you get your power windows and central locking to work, I didn´t find anything from the book, how to connect them.

    Margo, Estonia

  8. #8
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    Quote Originally Posted by Margo_325 View Post
    Im doing conversion on a 1995 Suburban. Donor car is 2001 Silverado. I have the book "Duramax 6600 Conversions&Repower Projects"

    My Suburban does not have an HVAC like in the book, I took all the wiring out behind dashboard (I want to keep the old dashboard), that included all heater wiring as well. Do I just have to compare two car wiring diagrams and search for right wires to connect to heater plugs?
    I only left the wires, that came out from drivers door and went behind dashboard to passenger door. How did you get your power windows and central locking to work, I didn´t find anything from the book, how to connect them.

    Margo, Estonia
    Your complete HVAC system & control panel should work just like mine does, meaning it'll operate as a standalone system. You'll just need to tap into DMax HVAC under-dash wiring for power/ground/AC clutch engage. I recommend using the Dmax HVAC power and lighting circuits so the correct the fuses are being used. The 88-94 diagram in the book can be used as a guide for your 95 system, but you will likely need the 95 wiring diagram to double-check it.

    As was mentioned by THEFERMANATOR, the ECM will be looking for the Dmax HVAC controller. I didn't need to delete that function in the ECM using EFI-Live, but it wouldn't hurt.

    If you want to maintain 4-wheel ABS, I would transfer the Dmax truck's ABS controller and related hardware to the Suburban.

    And by the way, I consider the Dmax instrument panel essential for the best conversion (the gauges are right and you'll have the DIC).

    Jim

  9. #9

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    I did put the Dmax instrument panel cluster in a Suburbans dashboard and fabricated a plastic cover around it. Also I did put a Dmax dip switch, that fitted almost perfectly. So for the HVAC I need just to connect 3 wires to make it work correctly (power, ground, A/C Clutch)? Unfortunately, I dont have Suburban wiring diagram, only the Silverados one.
    Last edited by Margo_325; 02-24-2009 at 05:43.

  10. #10
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    The pickup wiring diagrams should be virtually identical to the Suburbans.

    The HVAC package under the dash should have its own wiring harness - that connects to the HVAC control panel and the vehicle's original under-dash harness.

    I connected the original 1989 HVAC harness to the new Dmax harness connections for power/ground and Ac clutch engage. Works great.

    Jim

  11. #11
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    Default

    Well, 1st off, mine was an OBD II & you guys, fortunately are dealing w/OBD I.
    My Opinion:
    You need to get the GM FACTORY MANUALS!! It has all of the wiring diagrams.
    The A/C..As I recall, youall are on the right track-LOOK AT THE "a/c Request" wire.
    The 95-99(2000 for some) A/C wiring is the same. The control head is a computer.
    I'm not sure how you can get the 95 dash to work with the 01(DMAX) since all of the inputs(outputs?) are different & changed again several times.
    I used the 01(actually 01-03 I think)DMAX dash & it is usable/fitable(if that's a word)
    I need to read the posts again.......
    Gordon Marks
    Tampa, FL (Valrico, FL actually)
    99 Suburban C2500 W/LB7
    55 Series 1 3600
    33 Chevy 4dr street Rod
    64 Biscayne 409 NSS
    "10.81@124.65"]10.81@124.65 3920lbs.
    gordon@marksair.com

  12. #12
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    OH, the 95-99 A/C system controls are DEFINITELY different! They changed the controls & the dash. The basic system(box) is the same but the control head is alltogether different as is the wiring.
    The ducts are better too. The air flow/cooling(for those down here)is much better on the 95-99's but not as good as the later 2000's +.
    Gordon Marks
    Tampa, FL (Valrico, FL actually)
    99 Suburban C2500 W/LB7
    55 Series 1 3600
    33 Chevy 4dr street Rod
    64 Biscayne 409 NSS
    "10.81@124.65"]10.81@124.65 3920lbs.
    gordon@marksair.com

  13. #13

    Default

    Thanks, but I already subscribed as a member to alldata myself. Now I got the heater working (need to find the A/C engage wire, but I have some small problems left still. First, how should the coolant circle go through the heater? I have 3 pipe endings coming out from firewall, one I know is A/C pipeline, the other two are for the heater inside.
    http://stuff.e30club.org/images/suburban/hoses.JPG
    Problably the bigger one is intake hose and smaller outlet? Duramax has two exactly same size hoses, one is coming from the waterpump or near there and the other one is coming from that big hose, that goes to the radiator right side. Correct me, if Im wrong, but then the hot water comes from the lower hose, that goes to the radiator, goes through heater radiator and then goes back to the water pump? Of course, then it gets warm in car, when thermostat valve opens. And also I have A/C hose problems, if someone could explain me the schema, how I can fit them so my A/C fluid circle will be right. If someone can explain me, how I should fit those hoses, I´d be very grateful.

    Edited:
    Still one more little problem: I have that kind of wiper plug, that does not fit to the suburbans wiper motor, and it has 6 wires, but suburban has only 5, so any ideas? The Duramax wiper motor is different and cannot be mounted on the suburban body.
    Picture of my plug:
    http://stuff.e30club.org/images/suburban/wiperplug.JPG

  14. #14
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    Default

    Quote Originally Posted by Margo_325 View Post
    Thanks, but I already subscribed as a member to alldata myself. Now I got the heater working (need to find the A/C engage wire, but I have some small problems left still. First, how should the coolant circle go through the heater? I have 3 pipe endings coming out from firewall, one I know is A/C pipeline, the other two are for the heater inside.
    http://stuff.e30club.org/images/suburban/hoses.JPG
    Problably the bigger one is intake hose and smaller outlet? Duramax has two exactly same size hoses, one is coming from the waterpump or near there and the other one is coming from that big hose, that goes to the radiator right side. Correct me, if Im wrong, but then the hot water comes from the lower hose, that goes to the radiator, goes through heater radiator and then goes back to the water pump? Of course, then it gets warm in car, when thermostat valve opens. And also I have A/C hose problems, if someone could explain me the schema, how I can fit them so my A/C fluid circle will be right. If someone can explain me, how I should fit those hoses, I´d be very grateful.

    Edited:
    Still one more little problem: I have that kind of wiper plug, that does not fit to the suburbans wiper motor, and it has 6 wires, but suburban has only 5, so any ideas? The Duramax wiper motor is different and cannot be mounted on the suburban body.
    Picture of my plug:
    http://stuff.e30club.org/images/suburban/wiperplug.JPG
    In my 1989 Duramax conversion, the heater pipe closest to the engine on the truck's firewall connects to the upper heater supply hose coming from the Duramax engine. I bought a new silicone hose made for a 6.5 engined truck to sweep up and connect to the Duramax heater hose supply line.

    Wipers... I used a new complete in-cab wiring harness, and I maintained the original steering column. Using the 2001 harness wires used for the wipers, I made the connections between the wiper control stalk and the wiper motor (using the original electrical connector) using the 1993 wiring diagram. If your vehicle is newer and you're using the original steering column, use the matching wiring diagram to know what function each wiring connection is supposed to operate.

    Are you using the original steering column or a column matching your engine package (which is what I recommend for an easier install)?

    Jim

  15. #15

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    To Jim: I´m using a Duramax steering column as well. Theres minor problems fitting it, because the lower bracket does not fit and needs to be welded to another place. Same with the shifting cable bracket on the steering column, because Im using my original Suburban shifting cable (it is tight)

    To THEFERMANATOR: Could you explain it to me (a simple schema or something), because I have zero knowledges about relays. I know, that I have one wire, what turns on the light in the A/C button, if I give there "+" from battery.

  16. #16
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    Default

    The A/C control head in the 95-99 SUB's output's a 12V+ signal to the A/C system to request the compressor to come on. The 01 DMAX uses a ground signal from the controller to the ECM to trigger the A/C. So you would need to use a relay that is turned on by the 95 control head that would ground the A/C request signal to the ECM. And the A/C light in the control head is turned on by a controller inside of the A/C control head itself. Also the power for the blower motor in the HVAC comes through the origanal underhood harness that ran behind the engine and came down underneath the old coolant bottle. This is the same harness that origanally had all of the ECM wiring in it.

  17. #17
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    Default 98 K3500 6.5 to LB7 swap help

    Hello everyone
    I'm currently building a truck it's a 1998 Chevrolet K3500 crew cab dually, it has the 6.5/4l80e combo which is ready to pull. I'm going with a 03 LB7 and allison trans. I currently have the harness getting reworked by Ken Wolkens for a stand alone and have the ECM and TCM already reflashed. Now the questions I have is what is all needed to integrate the LB7 to work with the GMT400 platform? I was told the starter relay will not work along with the gauges, what is all reguired to get the HVAC system working with the 98 hvac and the lb7? and what other problems will I have to figure out? thanks

  18. #18
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    Post

    Quote Originally Posted by TheCanadianGoose View Post
    Hello everyone
    I'm currently building a truck it's a 1998 Chevrolet K3500 crew cab dually, it has the 6.5/4l80e combo which is ready to pull. I'm going with a 03 LB7 and allison trans. I currently have the harness getting reworked by Ken Wolkens for a stand alone and have the ECM and TCM already reflashed. Now the questions I have is what is all needed to integrate the LB7 to work with the GMT400 platform? I was told the starter relay will not work along with the gauges, what is all reguired to get the HVAC system working with the 98 hvac and the lb7? and what other problems will I have to figure out? thanks

    Many questions....

    First, there's no need to have the Duramax underhood/in-cab harnesses reworked. With the exception of splicing in the HVAC controller/package wiring into the Duramax in-cab harness, the rest of the original in-cab/underhood electrical will be stripped out and replaced with the Duramax harnesses, fuse panels and electrical centers. This actually makes it all a lot easier. Trying to jury-rig an old/new composite electrical system adds so much complication to the conversion that it discourages most who attempt it.

    The ideal is to create an electrical system that looks and functions like the factory Duramax system. The truck will be worth more at the end and it'll be easier to troubleshoot if a problem does appear.

    Here's a story about a 1998 Chevy LBZ conversion that used our motor mounts and Conversion Guide

    This Thread has answers for some of your questions.

    Our Duramax Conversion Guide has answers for most questions.
    Last edited by More Power; 02-10-2022 at 14:24.

  19. #19
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    Thumbs up

    I received this message and photo from Patrick yesterday. You can expect to see his truck on the road somewhere in Massachusetts before long!

    Jim

    From: PatrickS
    Subject: The Diesel Page - Duramax Conversion Mounts
    Date: Mon, 24 May 2021
    To: The Diesel Page
    Jim,

    The mounts arrived today and I was impressed with the quality of the parts. After work I bolted them up and, while an involved process, I got the drivetrain in. The mounts were worth every penny.

    Patrick

    2000 K2500, CrewCab Shortbox

    This above message was posted in may of 2021... just about 2 years ago. I received an update from Patrick a few days ago, along with an order for another set of our conversion mounts. I like his truck's new hood! Here's what Patrick said recently:

    These mounts are actually the second set I’ve purchased.

    A couple years ago I bought a set to put an LB7 in a 2000 K2500. I chose not to body lift it and instead made a HD hood. Attached is a photo of that truck.

    I’ll keep you updated on this trucks swap.

  20. #20
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    Question

    On 2021-04-27, mj m wrote:
    Good morning! I have a few questions about the Duramax Conversion Guide....

    I wanted to know if there were instructions for how to modify dash components in a truck prior to 1995... I know that you did this in your 1989 truck but was curious if the instructions are included in the guide.... Second, does the Guide specify which intercooler to use.... and the last question, are the engine mounts still available for purchase?
    Hello,

    Yes to all questions.

    I recommend modifying your original dash to accept the instrument panel from the truck matching your engine package. I did not go that route, but many others have. It'll require fabricating a "surround" that blends your original dash into the new instrument panel. Generally, a custom automotive audio installation shop would have someone with the skills necessary to do a great job - sorta like fitting custom speakers into a vehicle that didn't have them.

    That said, the Conversion Guide does show how I installed a complete new dash into my 1989 Chevy. It's a big job... If you go that route, I'd install the new truck's HVAC package and venting system along with the cross-cab aluminum underdash support. That way you'll be able to use the new truck's HVAC (heating, venting, air conditioning) dash control panel and the system's climate control... and it'll make for an easier installation. I also recommend using the new truck's steering column - for Allison shift function and electronics - plug n play. You'll just need to relocate the firewall mount bracket on the new steering column.

    I used a Dodge diesel pickup intercooler, but others have used a Duramax intercooler... I used a Dodge part because that's what I had access to in 2003. The Guide shows how to modify the intercooler and how to install it. An intercooler is essential for a performance truck or one that will be used to tow heavy. For a light-duty easy driven truck, the intercooler is more optional. I know of some who didn't install an intercooler and their truck did just fine.

    The motor mounts are still available.

    Thanks,
    Jim
    Last edited by More Power; 05-17-2021 at 07:53.

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