03 Montana. park lights stay on.

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RBWood

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2003. I assume it's a base model, but don't know.
Unless batt is disconnected or #7 maxi fuse (batt main 1), the park lights are on.
Disconnected bcm, ic, DRL fuse and module, column harness connector and even grounded park brake sw for the heck of it. No joy, no change. All disconnected at same time and individually.

Do think I have what is perhaps another unrelated issue. Disconnecting both rear light connectors does cause front side markers to dim so I plan to chase grounds for that, but do it it's causing a pwr on issue.

Hoping this is a known issue.

Many thanks!
 
are you saying the parking lights stay on with the light switch in the off position? All parking lights front and rear? If that's the case I would look at the light switch first maybe its faulty?
 
Yup, all park lights (forgot to mention it does chime as if sw on when door open).

This is with the light sw removed from the van.
Likewise for bcm, DRL, and disconnected column harness. All removed and all park lights still on. Obviously no chime now as it is in the removed bcm.

Thanks!
 
FYI on the light switch(above ur left knee) if i remember correctly there are 3 positions , auto position which I use pretty much all the time(parking lights and headlights come on automatically at dark and shut off when light enough) and a parking light position and then a headlight position, the last 2 are like a over ride .
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RBWood said:
Yup, all park lights (forgot to mention it does chime as if sw on when door open).

This is with the light sw removed from the van.
Likewise for bcm, DRL, and disconnected column harness. All removed and all park lights still on. Obviously no chime now as it is in the removed bcm.

Thanks!
Click to expand...

wow what a weird problem. you can always try a reset on the bcm and computer by disconnecting the battery for apx 30 minutes.
 
Not from any known history or evidence on vehicle. 2 owner we've had since 2005.

Batt was disconnected for over 24 hrs.
Did borrow a shelved known good bcm from a friend and was able to relearn pass sys and remotes. No problems but park lights remained on so I unplugged all the above mentioned in hopes of narrowing as I have no access to schematics to trace power at the time.
 
My reply didn't post??

Sorry. Anyway, not to the best I can tell no. No wreck history and we've had it since 05.
Starting to worry that I need to start looking for a critter nest hidden past my view thus far.

Batt was disconnected for a day.

Was even able to do a pass sys relearn and remotes on a borrowed bcm as a friend had one shelved. No dice and then started digging. I've just gathered up my electrical kit and power probe for tomorrow. Sadly I've had zero luck finding schematics.
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Without a drawing it does make it difficult, is there a parking light relay ? Or a automatic resetting circuit breaker? If so start there. A lot of times the relays are the same and you can swap them around for trouble shooting.
 
Fuses eliminated. Manual shows no relay, but I suspect there is something somewhere. I know there are within the drl (though it's been eliminated) and thus far Google hasn't been my friend.

Many thanks!
 
Anyone have wiring diagrams for light sw and IC (icl. Connector pinouts)?
I'm fairly sure my short is between the two.
With maxi fuse #7 (batt main 1) pulled, everything works normal with an exception. With the fuse out, the lights have to be turned on for the IC to power up.
Have to trace IC power and dash light wires/connectors.

Thanks!
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haynes manual has pretty good wiring diagrams. If I can remember where I left mine I'll get the publication number. It covers all the GM minivans since they're pretty much all the same except the trim.

Ray
 
Have a couple days off, so back on this.

Turns out there were 2 potentially unrelated issues. One is solved.
Still have the light issue and it's much closer now.
The IC is actually staying powered up, not just lit. Still altered by removing maxi #7 (batt main).
The offending wire is in the right hand IC connector and is orange (don't recall position letter atm, but it is in one corner.

I need to find source and trace on this wire to see why it's remaining powered as well as see where it comes into play on prk light circuit.

As before, with fuse removed all is normal save for lights needing to be on (any position) to power up the IC.

With fuse in, all is normal save for prk lights on all times (incl dash lights) and IC always powered (as in gauges still powered up).

Off to see what's what on the stepper motor from another suggestion.

Thanks!
 
Post attempt #I lost count.

Had 2 issues. Seemingly unrelated.
Remaining is only the light issue which is more specific now.
Turns out the IC is staying powered up at all times (as in gauges active).

Remove maxi fuse #7 (batt main) and lights are out, IC is off. IC will rremain off even when running unless lights are turned on (any position).

Off to dig around and try to find some schematics.

As to the manual, very fixed income and about $4 between the 3 of us atm. In a few weeks we can but would really be nice to have the only vehicle with a/c and able to get them both around (handicapped van). We're making do but can't get both into one vehicle till this critter is fixed.

Thanks!

PS. If there's a way to update the initial post, I'm lost there.
 
To update an earlier post use the edit mode in that post. Again good luck chasing them gremlins . Also could it be that the photo cell on the dash that turns the lights on automatically at night be bad and shorted on? Just guessing at this point.
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UPDATE:
It's sorted!
First off, in my digging, I have found this isn't an uncommon issue. Found 3 locally with the same problem. One came by and has just left. Got him to bring it by to verify same concern and repair. Another is at the local dealership and has been for over two months. The owner is going to demand her vehicle be put back together and then she's bringing it by.

If you run across this, find connector 203 (C 203) and cut the brown wire from both sides of the connector. Either splice the two together or splice in an independent connector. Locate the power wire for the optional rear air compressor (wire is there with or without the option). Splice it together or use a heavy independent connector.

Personally, I used a waterproof 2 wire trailer brake connector and used both terminals for one circuit.

Here's the catch. This info is good for 2002 to 2005 (maybe further but I have no access to verify).
Colors vary on the pump wire and I'm not certain that 04 and newer aren't married to the rear power port wire. Our 03 and his 02 had separate circuits though some schematics showed otherwise. His option wire was yellow/red and mine is red/blue (or gray, hard to tell). It is the larger wire (10-12) even though it gets a tiny data pin in the connector. A multimeter or power probe is almost mandatory.

Go ahead and pull the factory connector and clean things and use dielectric, but I suspect you are going to find the two terminals separate of the others have melted and shorted together. They are well isolated from the rest so you should be able retain the factory connector for the remaining wires. This isn't to say that you can't replace the whole connector, but keep this in mind......
The tiny connector pins for the option circuit (hot all times) is WAY too small for any load greater than an LED or two and is also used for trailer option if you have it.

Hope this is useful to someone!

Thanks!
 
Last edited:
thanks for the useful update
 
OK. Just took care of the 3rd van.
It is an 03, but with a production date of 05/03 so that may be a factor. Either there are 2 setups or hers is a change point for 04.

Either way, the power port and option wires are a single wire on hers until they split off at the terminal end of c203. Just removing the rear power port fuse corrected the issue (though I did repair it and replace the fuse). However, there was about 3 inches of burnt wire on the supply side of the connector. I just cut it back 2 feet and spliced in a piece of 10 to the new connector and replaced the option wire all together as she does have the compressor.

C203 was in different places on all 3. Mine is just inside the body, accessible by removing the inner pannel at the power port. The ssecond is just outside the body at same location. This last one (extended van) was just behind the rear axle beside the "frame rail"

The last one was obvious by the cooked wire insulation, but the other two were only visible by discounting c203 and looking inside.

Again, hope this helps the next person.
 
again thanks for keeping us updated, I'm sure somebody is going to need this information
 
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