NEED HELP disconnect/reconnect computer wiring harness

greggraves

Active Member
Problem is intermittent no start. According to TSB 03-06-04-012A "many times the vehicle may be repaired just by disconnecting and reconnecting the (wiring harness) connectors", specifically those that go to the PCM. I know I must disconnect the battery, but wonder if putting a 12V computer maintainer would be a good or bad idea. It is composed of 8 D-cell batteries to a plug into the cigaretter lighter.
 

C-ya

Well-Known Member
It would be good for maintaining the hvac door memories, but other than that, there is no real reason to do it. As The Roadie used to say, if it is weak to enough to fail while calibrating, you are better off knowing it while you are in the driveway, not on the side of the road in a snow bank at -20.

Good luck with the trouble shooting. Have you considered the ignition switch? It seems these cause all kinds of issues and they are inexpensive and easy to change. That may be a next step after the free t/s you are doing with the connectors.
 

Sparky

Moderator
I wouldn't bother with the computer retainer.
 

AtlWrk

Well-Known Member
It may sound strange but in this case it would make no difference at all. Both power ports connect directly to the battery (through fuses of course) so plugging in a computer saver will just maintain voltage throughout the system the same as the battery would (which IS useful for not having HVAC module reset as mentioned when you need to swap a battery or alternator) but not for removing power to the PCM (that's the whole point of the computer saver after all, right?).

If you were looking to remove power to the PCM before disconnecting the harness you can remove the 3 (or 4?) PCM fuses but frankly I don't think even that is necessary.
 

Sparky

Moderator
I think a big reason to disconnect/reconnect the harness vs just pulling fuses or battery is to reseat the connections.
 

AtlWrk

Well-Known Member
I was suggesting pulling the fuses to remove power to the PCM as an alternative to disconnecting the battery, not for resetting the PCM.
 

Mooseman

Moderator
I wouldn't disconnect the battery simply to retain my radio memory. But yeah, pulling the PCM fuses should work.

I've disconnected the PCM without cutting the power in the past lots of times, no issues. (Yeah, I know, it's not a good idea but I'm reckless :biggrin: )
 

MAY03LT

Founding Member
Lifetime VIP Supporter
The last time I had no batteries or memory saver hooked up in my tb was when I removed the pcm.
 

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