Name that part

[AugustDiesel]

So I have these random parts on the driver's side of my engine bay that aren't connected to anything. Can anyone identify what these are? Here are the first 2:

Note: I took this picture after reconnecting the wire to this part, but I'm not sure what its function is. The wire was just dangling below it:

3642

Then this:

3643

Thoughts?

I'll post some more later this afternoon

[trbankii]

I shall suggest naming them Fred and Ginger…

Seriously, though… Second one looks like a relay. From your signature, I’m taking that the 6.5TD was swapped in. What was the original engine - a 6.2? Or something else?

[AugustDiesel]

I shall suggest naming them Fred and Ginger…

Seriously, though… Second one looks like a relay. From your signature, I’m taking that the 6.5TD was swapped in. What was the original engine - a 6.2? Or something else?

Correct, it was originally a 6.2.

[Robyn]

Top piccy is the wiper motor

Bottom piccy is definitely a relay ????
Exactly what it controls/controlled is the Question.

Figure out what does not work and you may be able to solve the mystery

After sifting through the factory electrical schematic the relay may be the AC compressor relay.
The AC pump is on the drivers side of the truck.

Normally the AC relays are mounted near the evaporator case on the RH side firewall.

88 was a transition year when the Burbs and crew cab trucks remained the square body and the GMT400 series was introduced and lotsa stuff changed.

The relay also might be for the cruise control module.

Later electrical manual/schematics had pages dedicated to showing the location of various components on a diagram of the truck, but the early books just show ladder type schematics.

[Dvldog8793]

Howdy
Wiper motor and what appears to be an aftermarket relay(judging from the screws)
The relay could have been used for anything.
It may have had a single plug but most likely had three wires with spade connectors.
If you have an after market accessory that is not working then that would be suspect. Whatever it is for, from the looks of the terminals, it hasnt been hooked up in awhile....
Hope this helps

[AugustDiesel]

Awesome thank you all. I think it's interesting that the first item is the wiper motor, because the wipers were working prior to me reconnecting the wiring to the motor! But then again, I have only put about 1,300 miles on the truck since I bought it back in September 2016 (this includes driving it up from South Florida), so I haven't really given it a hard rain test yet.

There is this other little gizmo, attached to some wires, that is laying loose on my inner driver's fender, somewhat near/below that relay. I will snap a pic of it this afternoon and post it to see what y'all think.

[JohnC]

...and what appears to be an aftermarket relay...

If it was a relay I'd expect it to have (at least) 4 connections.

[DmaxMaverick]

The wiper motor may have 2 connectors, which I believe yours does. The upper connector is for the "park" disc switch. The wipers will work with the upper disconnected, but may not park correctly.

The relay, if that is what it is (appears so), can be correct with three connectors. The 4th pole is the grounded case (which it appears to have). Many OEM horn and driving/fog lamp relays have a three wire connector.

[Robyn]

That certainly could be the horn relay :):)

Try all the equipment and see what does not work

[AugustDiesel]

There have also been some suggestions that the relay could be related to the air-conditioning system, but the AC is on the passenger side of the truck and this relay is on the driver side of the truck, here's a shot of my AC connections on the passenger side:

3644

Here is the other gizmo that I was talking about. It's just laying there on my drivers inner fender doing nothing. Seems to be attached to some sort of cable perhaps.

3645
3646

As far as the relay goes, I do not see anything laying around nearby that looks like it should be attached to it...

[AugustDiesel]

There have also been some suggestions that the relay could be related to the air-conditioning system, but the AC is on the passenger side of the truck and this relay is on the driver side of the truck, here's a shot of my AC connections on the passenger side:

3644

Here is the other gizmo that I was talking about. It's just laying there on my drivers inner fender doing nothing. Seems to be attached to some sort of cable perhaps.

3645
3646

As far as the relay goes, I do not see anything laying around nearby that looks like it should be attached to it...


Turns out it's a CB radio antennae base :D

[Robyn]

The AC evaporator box is indeed on the RH side of the rig.

The relay there in your piccy is the blower relay. (mounted to the evap box) and controls only the heater/AC fan speed.

The relay on the drivers side we discussed may be the relay for the AC compressor clutch

Trace the wires from the AC compressor back and see where they lead.

There is a low pressure switch on the accumulator (Silver can on the evaporator box outlet)

The switch controls the compressor, but there may have been a relay in the circuit as well.

Once stuff gets hacked up over the years it can take some serious snooping to figure out how MA GENERAL had it originally.

[Robyn]

Digging through my 89 schematic and the relay on the DRIVERS SIDE is not related to the AC.

SADLY the schematics of the early trucks do not have a "component locator sketch)

This said I went looking deeper and did find a relay thats used for the power door locks.

Does your truck have power locks ???? and if so do they work ???

[AugustDiesel]

Digging through my 89 schematic and the relay on the DRIVERS SIDE is not related to the AC.

SADLY the schematics of the early trucks do not have a "component locator sketch)

This said I went looking deeper and did find a relay thats used for the power door locks.

Does your truck have power locks ???? and if so do they work ???

Yes, Rusty does have power locks and windows and they do work. I will say that the AC, while it does work, doesn't really blow real hard unless I get up to highway speeds.

My headlights are all wacked out though (see seperate thread), but I don't think this is related. There are no connectors in the headlight harness anywhere near this relay (nor any other connectors for that matter).

Other than those things, I don't think there's anything else that's not working. It's possible the relay could be related to the CB cable/antenna base I identified earlier, since they are near each other. I know in that same location, there is a thick power wire running from the driver's side battery into the cab and into the center console, but then connects to nothing. Seems likely that the actual cb radio was located there, then perhaps the whole cb system was removed prior to my purchase. According to another individual, the antenna base is for a K40 CB radio antenna, which had a twist lock feature to remove the antenna to prevent theft.

[DmaxMaverick]

You may have ID'd your aftermarket gremlin. A CB radio doesn't require much in the way of power and big cables (a few amps, at most), but a linear amplifier does (20 to hundreds of amps....wow, that brings back memories!). Relays and large power cables wouldn't be unusual for a CB'er pushing some serious power.

[AugustDiesel]

New random part: this is located underneath the dash right behind the pedals, just hanging out....


3653

[trbankii]

Looks like a floormount headlight dimmer switch - but (obviously) could be used to switch other things.

[AugustDiesel]

Looks like a floormount headlight dimmer switch - but (obviously) could be used to switch other things.

I can tell you that it's a push-button style switch, but what it operates I don't know.

[Yukon6.2]

I know that a lot of old school drivers would add a foot dimmer switch for auxiliary lighting.
In the Time before mulit switches on the column,hitting the foot dimmer used to be instinct.

[AugustDiesel]

I know that a lot of old school drivers would add a foot dimmer switch for auxiliary lighting.
In the Time before mulit switches on the column,hitting the foot dimmer used to be instinct.


That's possible. There were once 4 auxiliary lights mounted to the bumper, but the harness for them was missing so I removed the lights. Still have them

[highdesertranger]

that thingy in post #10 is an antenna mount base most likely for a CB. highdesertranger