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View Full Version : 4L80E wiring diagrams....



barebackjake
07-20-2004, 19:35
does anybody have wiring diagrams for this piece of crap? my van has been in the shop two weeks now, first the tranny exploded in it, it got rebuilt, now im getting a tcc code says no brake switch, well brake switch open. well brake switch is working, getting signal to computer. now there thinking its a pcm failure. which is what there thinking made the tranny fail the first time, but then it wasnt showing any codes, im about to light this thing on fire, damn tranny cost 4000 and now what.....

anybody wanna buy a 97 14' box van aluminum body 105k mi????

Paul Amestoy
07-21-2004, 12:24
Try this link... it has helped me in the past..

http://www.454ss.com/Articles_new/red/4L80E_Transmission_Problems.asp

Good luck

barebackjake
07-21-2004, 18:20
thanks for the info paul

its a start, its driving me nuts, getting really frustrated with this thing, been one after another
trying to find out why the computer is getting brake switch signal but not processing it

Paul Amestoy
07-21-2004, 20:59
I have found that the connectors and grounds are horrible.... probably lots of low current signals that require decent connection.... I had an air bag error and the dealer wanted $ 1500.00 to fix it... eventually I regrounded the computer and dash to the battery terminals and it all worked better...no errors and the damn thing ran great... I was just thinking I had to get down under that thing and use contact cleaner and clean all the 150 or so connectors.... enjoy... what part of california do you live... I am in so. cal and it is impossible to get a good mechanic...

CareyWeber
07-22-2004, 01:28
Originally posted by Paul Amestoy:
I have found that the connectors and grounds are horrible.... probably lots of low current signals that require decent connection.... I had an air bag error and the dealer wanted $ 1500.00 to fix it... eventually I regrounded the computer and dash to the battery terminals and it all worked better...no errors and the damn thing ran great... I was just thinking I had to get down under that thing and use contact cleaner and clean all the 150 or so connectors.... enjoy... what part of california do you live... I am in so. cal and it is impossible to get a good mechanic... Paul,

Can you explain exactly how you grounded the dash and the computer? Do you have any pics of what you did?

Carey

barebackjake
07-22-2004, 05:43
yeah i havent found anybody decent down here to work on this thing either, im in san diego area
i love to be able to get to that dang computer but they put it in the middle of the dash all the way almost to the windshield, so its about 2 feet deeper than the radio is. makes you wonder how much crack that engineer was on before he thought of that ??? im gettting rid of this pos right aftrer this is all set, its been one after another and im into it more than what i spent now, should have seen a sign when i had my dmax for 3 weeks.....(thats another sore subject)

Paul Amestoy
07-22-2004, 05:50
My computer is directly behind the glove box and is very accessable.... The grounding for the computer is direct above the computer... I found a ground differencial of about 2 volts at this point... I then ran a 12 gauge wire from that point to the ground on the engine ( passenger side toward the rear of the engine ) I also ran an extra battery ground from the passenger battery to that point on the engine... I then used that as a known good ground and have put a ground block at the firewall at that location and whenever I find a ground ( anywhere ) I run it to that location....
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