About a month ago I started using my '91 5th Avenue again as my truck is falling apart. When I went to use the wipers to clean the windshield, the wipers did not work at all, but the washer did. Figuring I had a "flat spot" on the rotor, I pulled on the wipers a little and they began working again (I did strip one wiper arm but a junk yard in NH gave me one for free). This past weekend I tried the wipers again and they did not work. Not wanting to strip another wiper arm, I decided to just check the motor.

I pulled the motor out and cleaned the rotor, bars and magnet surfaces (the motorwas rusted and wet inside so water had gotten in at some point). I connected the motor wiring harness and the motor worked when I turned on the switch, so I began reassembling the mounting plate. Before I connected the linkage and put the cowl back on I tried the wipers again. Nothing. I could see the alternatorgauge needlefluctuate slightly every time I turned on the wiper switch, like you see when you turn on the lights or any other significant load, and I could hear a clicking soundfrom the passenger side under the dash.

So I pulled everything apart again and checked the motor with a 12v source and it ran fine. I then checked the hot wire at the harness and got indication it was working. Of course, not only does the Haynes manual have vague sections on the wiper motor, it does not have a schematic for the wiper system.I called the local dealership to see if there was a relay or module for the wipers (the Haynes manual indicated the wipers were controlled by the BCM). They said they could find no relay or modules for the wipers. So I plugged the harness back on and tried again. The motor still did not run and this time the alternator gauge needle did not flinch. I checked the fuse and it was still good.

Today, thinking the ground could be bad, I check the wiring harness ground wire and got nothing. So I jumpered a wire from the car chassis to the motor's black wire and plugged in the harness. When I turned the wiper switch to Hi, the motor worked but as soon as I turned the switch from Hi to either Lo or intermittent, the fuse blew. After blowing a 2nd fuse trying the wipers again, I put in a 25 amp fuse (I know, shame on me; but my intent was to just quickly check to see if I could get the motor to work at any setting other than Hi). This time the fuse did not blow, but the motor would only work on Hi.

So, is the issue here with the BCM? Does the BCM contain individual component modules that can be replaced? If not, can the BCM be "flashed" or reprogrammed and would this have a good chance of resolving the problem? I really do not intend on spending over $700 for a new BCM on a car that is worth, at best, maybe twice that amount.

 

Wondered what the end result to your problem was? I have same model and year and same ticking under passenger side dash

 

I've used these guys, great work, good people.

http://www.sp-ecu.com/AES_Automotive...ions_Main.html

They not only fixed my BCM, but as they know the problems/problem parts that break in BCM's, they replace the parts known for past breakage with higher quality parts than factory.

Burn