Chevy & GMC Vans

So I am going through the motions on installing new speakers in my rear doors, drivers side is good - nothing unexpected. Passenger Door I remove the speaker and find additional wires that I was not expecting - I realize that this side has additional wiring to the rear license plate light, but what is this 4 wire harness (refer to attached photo). I assume it is an additional trailer wiring hookup? I already have the lager trailer wiring loom wired to an 9 pin plug on the bumper so just curious - anyone know what this is? We're talking a 2001 Astro AWD LT - refer also to sig. below...

Thanks one and all! Cheers

Mystery Wiring

BUMP - just wanting to get this in the radar - after tonight if I don't get an answer I'll (and after I renew my library card) I'll pull the wiring diagrams and see if I can track it down.

One last bump before I let this issue die - and then really dig into it this weekend - of course when I figure out what these are I'll keep everyone posted.

Do you have the dutch doors? Could it be for a rear window defrost or wiper?

I'm not sure but it looks like a plug that would connect to a motor. My guess is wiper but that's usually not an option but a standard item isn't it ? Guess the later vans had rear wipers,,right ? If they were equipt with wipers as a standard maybe you've had a door replaced that may not have had a rear wiper.
Just a guess now,,I don't have a clue what came with the later models and what didn't but it sounds good.

From what I gather he has dutch doors. My question is, does he have power locks and if so do the work the lower doors unlock properly? To me the only logical things wired into the passenger side door would be power locks, plate light, and speaker. Defrost and wiper would be wired into the lift gate. Maybe it's an unused barn door defrost connection. Could use a check light to see if any of the wires are live, then check again after the rear defrost is turned on.

ihatemybike wrote: Defrost and wiper would be wired into the lift gate. Maybe it's an unused barn door defrost connection.

Good thinking. If he has Dutch doors it isnt for wipers or defrost. If Barn door maybe still as well you know GM just leaves things laying around ;p

Thanks for all the ideas - I do have dutch doors! I have been looking at wiring schematics this morning and thinking - hey maybe its something left over from the cargo door type vans..... so now even more so.

Correct me if I am wrong - but in my lift gate I have the wiring for the defrost, wiper, and locks. I don't beleive there is any lock in the dutch style lower doors is there? Don't they just rely on the upper gate latching over the lower doors?

I'll get the meter and test light out this weekend to try and nail this down....

thevalleyboy wrote:
Correct me if I am wrong - but in my lift gate I have the wiring for the defrost, wiper, and locks. I don't beleive there is any lock in the dutch style lower doors is there? Don't they just rely on the upper gate latching over the lower doors?

I'll get the meter and test light out this weekend to try and nail this down....

On my '94 LT ,the wiring runs to the speaker,license plate light,and both the key lock and door latch. Sounds like one of the locks wires are disconnected.Let us know how you make out.

snapple wrote:

thevalleyboy wrote:
Correct me if I am wrong - but in my lift gate I have the wiring for the defrost, wiper, and locks. I don't beleive there is any lock in the dutch style lower doors is there? Don't they just rely on the upper gate latching over the lower doors?

I'll get the meter and test light out this weekend to try and nail this down....

On my '94 LT ,the wiring runs to the speaker,license plate light,and both the key lock and door latch. Sounds like one of the locks wires are disconnected.Let us know how you make out.

On the earlier dutch door vans, there was a switch that took a key that opened the hatch right by the licence plate. It had a similar looking plug. I put a push button above the license plate (kind of by the lamp) and hooked the wires to it. Couldn't see it, and didn't need a key.

Confirmed that it is not the power door lock wiring - that works fine....

Well I hate to admit it - but I give up - tried the defrost - wiper - door locks - audio system? - aux. lighting (worth a guess) - trailer wiring (another set?) - but I cannot find a use for these wires - so they are taped up and returned to the passenger side dutch door cavity for a time... so the mystery continues.... Cheers to the treasure hunters whom helped....