Electrical problems with my 2000 LX 2.3L. SRS, ABS, MIL, door/trunk/brake lamp, battery indicators started coming on in the evening. In the morning the battery was completely dead, no relay clicks or anything. Jumped it, as soon as I started it both rear windows went down and stopped working. Replaced both window fuses, both blew again when key was turned to ign (II). Car running so I dropped it off at a local guy who has been okay for diagnostics and complex stuff before. Called back, alternator’s voltage regulator bad, and the car’s voltage spiked. His mentioned having possibly fried the ICU? I can’t find any good info on this online, and need to know more about these units. I have a shop manual on the way to help figure out the diagnostics on this and have some other options lined up since the estimate at the shop obviously isn’t feasible.

Anyone who can give some info on the ICU or which electronic components I can expect to be fried from this voltage spike and diagnostic tips for checking out the system. I’m getting the alternator tomorrow and will have the car back Monday morning. Thanks.

 

man ... you are all over the place ,,

 

Thanks for your useless reply. This is a big problem and I don't have time for people who don't have the automotive background to understand it. Anyone else...

Okay, this is the current situation. I replaced the alternator with a high quality rebuild. The car is running fine and the MIL/CEL is not lit. No other indicator lights are coming on, which should indicate no ICU failure (my wiring diagram refers to these as multiplex units).

I replaced the blown rear power window fuses (20A). Turning the key to II blows them instantly. I then removed one of the rear door panels and accessed the power window motor and switch wiring. With the key at II and the switch connected, there was no motor response. With the switch disconnected, I was able to confirm 12V at one terminal of the switch connector. I then jumped the 12V directly to both terminals of the power window motor and there was no response.

I need to know the nature of the power window circuit. With the 20A fuse blown, I am assuming that the power window motor is still grounded. If this is the case, and I have no response from the motor, can I safely assume the motor is blown. If the motor is blown, is there any way it will blow the fuse when the key goes to II. Anyone heard of a blown window motor blowing the fuse when the key goes to II? Any info is appreciated.

 

ICU? Is your car in the Intensive Care Unit? Or does your extensive automotive background have an alter definition for this ICU? Maybe you mean ECU?

I would try to get/borrow a know good ECU after you get the alternator replaced and swap it in to see if it eliminates the problem. If that doesn't work, you may have to physically inspect the wiring around the fuse box. How long have you had the car? Did you check to see if it's from a southern area originally (possible water damage). Check the wiring under the steering column to see if maybe it had an aftermarket alarm and it wasn't properly uninstalled. Electrical problems are a PITA. Good luck.

 

do you mean Engine Control Unit (ECU or ECM) or Electrical Load Detector (ELD)?

Since your car runs I doubt it is going to be your ECU but your ELD could be bad. replace the alt and see if the problems go away.

 

Multiplex Control Units (modules),
I think your tech may be looking in the right direction, but you've caught him miss-stating. The ICU (as I understand it) stands for Ignition Control Unit)
If you were a victim of the now infamous Denso Alternator overcharging scenario, consider yourself lucky (Lucky he says?) I've seen blown bulbs, Ecm failures and Hydrogen Gas battery explosions from over charging.

Let me get the wiring diagrams out...
Each window motor incorporates a circuit breaker. they are wired directly thru their individual switch (which controls polarity). In other words, the window drive motors are Not internally grounded. They are both powered and grounded thru their respective switches.

P

 

Yeah check the simple stuff first...like a short to ground somewhere that might be causing you all those trouble. If I have my wiring schematics here I would tell you where to look..but sorry I don't.