Electrical demon

2000 Montana

In one single trip, my power sliding door, rear window wiper AND automatic locks (when putting the car in Park and in gear) stopped working. (The automatic locks work...they just don't lock the car when you put it in gear or unlock the car when you put it in Park.)

This is too much of a coincidence to be three separate problems.

However, I can't find any common relationship between the three at the fuse box.

I tried the reset procedure for the sliding door to no avail.

Could this be a bad BCM? There's a possibility that I fried something, because I repaired the ground wire on the left rear indicator lights by completely bypassing the plug and soldering everything together. The ground connection of the plug had essentially melted away. When I did that, I accidentally had a little drop of solder shorting between two of the connections. When I found the lights didn't work correctly, I looked at my solders closely, repaired the connection, and everything in the rear lights works perfectly.

But, now I have these three NEW problems.

Any ideas?

I figured it out, but have a new problem.

The Backup Light fuse was blown. That caused the door and lock problems. The rear window wiper seemed to fix itself.

However, now I can't figure out why I can't keep the backup light fuse from blowing.

I bypassed the plug to the left rear turn signal because the ground connection had corroded away. I just matched the wires up to the pins and soldered it together.

Now, I keep blowing backup light fuses. I checked and re-checked my solders and even re-soldered them tonight very cleanly.

Any ideas?

Is any of the wiring going to the left side melted. I would ohm out the wires to ground and see of you get a reading. You should get a ohm reading of infinity if not, you have a wire problem. The hot wire is shorted to ground causing the fuse to blow.

I bypassed the plug to the left rear turn signal because the ground connection had corroded away. I just matched the wires up to the pins and soldered it together.

What do you mean by bypassing the plug? You should have a 12V wire coming into it and a ground going out from it. The bulb would serve as the load and will light when 12V appears on the 12V wire. If you bypass the plug, you have created a short. But maybe I'm misunderstanding.

I think that he soldered wires to the backup bulb. You should replace the bulb socket if you have not done so already.

The brake light, backup light, turn signal and driving lights are all part of a circuit board.

The plug with five wires that plugs into that circuit board is bad. The ground connector has corroded to a nub.

So, I bypassed the plug altogether, and soldered each wire to its corresponding male connector on the circuit board. Unfortunately, the plug is unavailable to purchase separately except as part of a huge wiring harness or used through a scrapyard.

Make sense?

This is a common problem with the model years around 2000.

That makes a lot of sense then. I would try a junk yard then. If possible can you take a pic of the pc board I might be able to fix it for you. One thing you might try is a self resetting circuit breaker in place of the fuse if possible.

Calling it a "circuit board" is a little misleading. Inside the plastic casing that has the four bulb sockets, there is a network of thin sheet metal strips all cut to run very close to each other and carry current properly among the bulbs based on the input of the four incoming wires. The fifth wire is the ground. I think this was probably a manufacturing decision. It's probably easier to manufacture these thin sheet metal strips rather than actually WIRE everything the old fashioned way.

Somewhere in that maze of sheet metal, I must have cooked something (or maybe even just bent something) that's causing a short in the backup light.

I ordered the whole plastic thing with the sockets and the circuit board off eBay for about $30. I might contact a scrapyard today and get a used plug so I can put everything back together correctly.

By the way, you'll know if your ground is bad if you have one of these models when all the lights in the back and the flasher lights on your dash go crazy. For example, every time I turned on the left turn signal, it worked fine until I stepped on the brake. Then, both of my dash lights would light up and the flasher stopped. It all has to do with this ground wire being corroded away over time. Conventional wisdom is that it's a design problem because it's a really common complaint as the vans get older.

So, you can imagine my confusion when I successfully fixed my problem, and a day or two later the locks and power sliding door stopped working. I never dreamed it would have anything to do with a blown reverse light fuse!