How to test the BCM

[pappyl]

So it's on the firewall side - once of the big fuses?

[sandrock]

I am surprised this wasn't mentioned yet. There were two different model numbers for the blower control module, and neither one will substitute for the other. There were, as far as I know, two failure modes. One where the motor won't come on at all, the other where motor is stuck on high and will not shut off at al, even after powerdown.

Now, you state you tested 8 of these modules, none of which worked. If they came from a junkyard, it's entirely possible that none of them work...as Don already said, they are a high-failure item. Mixing the part numbers together also makes this entirely plausible.

I read in another post that the PCM may be at fault. IT ISN'T. PCM has absolutely nothing to do with blower motor control...the only thing it does in relation to climate control is commanding the A/C compressor on or off after it is told by the climate control unit to do so.

Why are you looking for a fuse? Everything is getting power like it should, so why look for a blown fuse?

[pappyl]

sandrock,

See gmman's posting for Mon May 25, 2009 12:05 am ... should answer why the fuse...

During my junkyard search I did encounter another BCM model - different plug setup. I think they're not interchangeable.
note: I used rockauto to cross reference the number of models which have alike HVAC systems.

I can turn off my fan, w/o issue. Even on, when I turn off the key, the fan stops - no running over.

So maybe the BCM is fine - maybe the problem is with the control panel. I don't have another CP to test that theory as yet is the problem.

Maybe I am stuck until I fork out the money to by one from the junkyard - when I find one.

[pappyl]

Went to the library today - pulled a wiring diagram.

I see where the 1-amp fuse is - for the blower feedback. It's in the relay centre (right hand side I believe)

I'll check it...

[gmman]

that would be the right one. i have been looking at the troubleshooting procedure in the 96 FSM and it does suggest checking that fuse for hi only blower operation.

[pappyl]

Wouldn't that be nice if that's all it is...

There's a purple out, orange line in and a 10A fuse (not 1 amp), Fuse #11....

[pappyl]

That was it - problem SOLVED!

For those who may experience same issue...

- Passenger side, fuse centre on right by kick panel.
- There are 3 fuses second row from bottom. The fuse in question is the one closest to you, farthest from the firewall.

Problem exposes itself as:
- only high speed on fan
- BUT everything else works properly



BTW - I didn't thank everyone for their help on this - a big THANKS to all of you - especially gmman.
I know if i'd brought this into the dealership the fuse would have cost me at least $500...

[pappyl]

old problem - never did post the answer... sorry.

If anyone has the same issue - here was the answer..

Bad fuse on the fuse panel - passenger side. Believe it said ac/misc.