Ok, here’s my problem.
Background… 1997 Z28 m6 @ 86,000 K miles, bone stock. At times, usually for short durations the power gets lost to both windows and the radio, always at the same time and for the same duration. When I cycle the switch for the power door locks the circuit gets restored to the windows and radio, but sometimes only for a few seconds, sometimes for days or even months. I have replaced the driver side window motor three times and switches twice and this problem persists. I’m wondering if it’s a bad ground somewhere, but from looking at a Haynes manual schematics diagram I can’t find a common ground between the windows and sound system. So I’m asking you guys if anyone has had a common experience for ideas, advice, a permanent solution, hell, I’ll even take some ragging for being stupid.
Thanks in advance.
J.B.

 

Have you considered the RAP module under the dash?http://shbox.com/1/express_down1.jpg. This is just the first thing that came to mind.

 

Thanks for the reply.
After work today this problem became worse than it’s ever been so
following your advice I “checked” the R.A.P. module that you pointed out. Not knowing exactly what to look for all I could find was that it is present and that it was warm to the touch, but I attribute that to be due to where it is mounted. All of the wires were firmly seated and the module was very clean. My manual does not address this particular component so I have some questions… What purpose does a R.A.P. module have in the existence of my car? Which systems does it effect? And how can I test it further?

I’m still thinking that it’s a bad ground somewhere, but I am an aircraft structural mechanic and my knowledge of electricity and electronics is limited. More direction is needed, and as always, thanks.
J.B.

 

How did you find something that doesn't exist?

In 96 the RAP module was deleted and the functions of the RAP were incorporated into the BCM. RAP means retained accessory power. The BCM is however located near the radio and AC under the dash. This is were the confusion may have come in.

There is a common ground for all the systems you mentioned and it is located behind the drivers side kick panel.

However, if you think about the problem and do a little investigation you may find the problem is simpler than you think.

The (RAP feature of the) BCM will continue to feed power to the door locks, mirrors, windows, radio and remote hatch release for 10 minutes after the ignition is cut off as long as the door(s) is not opened. This gives you some creature comforts until you exit the vehicle.

If a door is opened, the radio and power windows will shut off. However, the door locks, mirrors and remote hatch release will work for 35 seconds after the door is shut.

It appears from our point of view, the BCM is not seeing the door switches correctly. The door switch grounds when it is open. Therefore it may be reasonable to assume that one of the door switch inputs to the BCM is intermittently touching ground. The first thing to look at is either the grey/black wire going to the BCM or the black/white wire to ground while you wiggle them. Incidentally, the wires for both switches pass through C200 which is an 18 pin connector located behind the same driver side kick panel. The problem should not be an intermittent connection since the door switch has to appear grounded as if the door was open. It should only be intermittent to ground.

Another place to look is under the carpet/threshold. It's possible the door switch wires got caught and possibly pinched causing them to touch ground.

 

Thank you, Speedy! I did notice some subtle differences between my car and Shoeboxes' picture, but I just thought it was because of the model year difference.
What you posted makes a lotta sense. I'll look at this from a different perspective today after work.

 

Aren't the windows and locks on breaker protected circuit in the fuse box? Maybe the radio is wired into that circuit as well. Just a thought....it may be the circuit breaker.
Doug

 

check contacts on ignition switch

 

Wouldn't the RAP or BCM only come into play if the key is off and the doors are shut??

It sounds like this problem occurs when the car is running but maybe I can't read so good

 

common ground is bad news for business haha

i know with late model explorers and many fords in general (sorry for the f word) the BCM goes to "sleep" after a short duration. I'm familiar with viper alarms and such the equivalent.. there's a provision to wire to the BCM to "wake up" the system.

while "sleeping" many of the accessory functions such as windows and power locks often stop working until the system functionality is restored.

In late model camaros the main control for the windows and locks is the passenger door (don't know why but it is). pull your panel and check for shorts and make sure everything is plugged in securely. hope it helps.

 

You can read just fine! Yep, it's happening when I'm going down the road. I'll tear into it later today and apply the knowledge that speedy has bestowed uponto me.