Spook in the electronics

[ColoradoReatta]

My 88 dash and CRT works just fine when cold out,below 35 degrees and will do so until the ?????? warms up. When the car, or interior warms up the dash and CRT work fine on start up, the computer goes through it's checking program, THEN, before the CRT can state "NO MAFLUNCTIONS" the CRT and dash go blank. At that point a number of functions quit working, such as the high beams, fog lights, heater, etc. The computer with the CRT keeps trying to rescan and can't complete its scan gives up and the CRT displays the radio only, a few seconds later the CRT goes glank again and stays that way for awhile. Minutes later the CRT comes back on and tries the scan again, fails, goes blank again, this continues to cycle forever as I freeze. The BCM and ECM were both replaced in 2000 by a dealership. Do any of you have any thoughts on this?

[padgett]

Yes, either central power supply or BCM. Of course that is only what I would check first but something is failing under load (or has failed and takes the system down when turned on).

[ColoradoReatta]

Padget, when you say central power supply, can you be more specific? Where is it located, what does it look like? Is that the description that I use to orded a new one?

[Rawja]

The central power supply is located above the driver's feet. To get at it you'll need to remove the black plastic shroud (the footwell lighting is mounted within it) and you'll see a silver metal box mounted vertically above the footwell up in the dash.

If you contact Jim Finn JFinn@cpinternet.com he'll hook you up with a used unit for a great deal le$$ than anyone else will.

[tnheygirl]

I have had this exact problem for years now. I have an 88 too. Replaced everything under the sun. The only thing I have not checked is whatever is in the steering column. I noticed after a couple of years, if everything shuts off as usual, and I turn the car off and slightly wiggle the key as I am cranking it everything comes back on, dash lights, heater or air, radio, ect. Or if I crank it and none of the above come on, I can shut it off and wiggle the key upon cranking and tadaaa its back again. Its something in the steering column I think because if I don't wiggle it just right while cranking it won't come back on.

[padgett]

Those intermittant and heat-related things can drive you batty. At this point I would be pulling fuses/relays starting with high load items - cooling fans, heater fan - that do not turn on immediately and see if one of those circuits was the culprit. I would also instrument the RUN line to the BCM, the 7vdc line from the CPS, and put an ammeter on the battery (I assume this occurs whether the engine is running or not ?)

If that didn't work, then I'd start swapping major modules from my spares but that option is not available to everyone.

Have had a lifelong dream to retire and open a shop specializing in electronics, since my wife gave me a Real Compressor for our anniversary now have about everything 8*). Of course that would last right up to the point of actual opening. Prolly have to advertise Free Beer and a singing frog.