Doc,

I could be wrong, but following the schematics in the service manual, I find NO battery supply routed thru the Relay Control Module except that which goes thru the Engine Control Relay, Traction Relay, Air Pump Relay, Horn Relay or Fuel Pump Relay - EXCEPT for the Black/Dark Green wire going to the PTCM. I simply don't see the RCM as a "battery B+" path, and I've printed 8W-10-1 to 8W-10-23 of the manual. THere is simply no path there. Now if it was an engine dies, but power to the four ways, etc. is still there, then SURE, it's the RCM!

The best clue he's given us, is that the four ways would not flash. This is largely a Body Control Module issue. So, where does the BCM get it's non-switched battery power? (This is the question to ask, since we know the four ways are powered without the switch AND the four ways are a BCM - operated accessory.) If we can find the failure in power to that circuit, it stands to reason that we can find the failure, period. (I know you'd THINK it was the Illumination Control Module that operates the four-ways, but in this case, it's not.) Answer: Fuses 9, 16 and 19 of the Underhood Accessory Fuse Block.

This power ALL comes from SPLICE BLOCK 100, which is fed by the 200 amp fuse in the little black box near the battery (the one I previously said had grounds in it.) This fuse is powered from the battery with a large cable that is the SMALLER of the two cables coming off the battery positive terminal. Unless the 200 amp fuse is bad (not likely) or the nuts on that fuse are corroded/loose, I still blame the battery/battery connections/battery cables. Sure, one of the other fuses COULD be bad... but I don't see that. I guess opening the fuse box and pulling those fuses to see if they have been allowed to get wet and corroded would be a good idea.

A loose connection on splice block 100 is another guess. Problem is, I cannot find where splice block 100 is - in the box with the RCM/PTCM/BCM???? Does anyone know?

I'm not there, but I STILL wonder about the battery connections, including the tightness of the ground screw on the negative/ground battery cable.


I cannot see where the RCM solder joints could cause this "total power down". But I would open that little black box and verify that the cable from the battery positive terminal going into that box has it's nut TIGHTLY secured to the bus in there!