SRS Fault - Fuse F23 blowing - why?

GRC50 said:

Well it's been 2 years and I still haven't fixed the fault, so I thought I'd take another look at why the red SRS light is on and the "Airbag Fault" message appears.

I was poking around the fuse box because the A/C has crapped out again (clutch has zero volts ) and I noticed that fuse F23 (10A) had blown. I replaced it with a new one, switched on and it immediately blew again.

Unfortunately, I can't find anything about the SRS circuitry in the ETM, just a simple diagram in Section Y2 Page 10 (Fuse Details) which shows that it's between the fuse box and Airbag Diagnostic Control Module.

Any ideas what could cause F23 to blow?

I've trawled the net without success, and my local mechanic is stumped as well. There is no fault code registered on his test book, so there's nothing to reset / clear.

Had a root around the bright yellow cable harness under the dash and couldn't see any loose connectors. No obvious damp or water damage anywhere (ambient temperature currently 35 degrees here so everything is hot and dry).

The fuse box has already been replaced and I've checked the relays. Does that just leave the rotary coupling? Can that be tested simply? I'm concerned about messing with the SRS system given all the warnings about exploding airbags etc. in the workshop manual.

My 1997 P38 4.6 HSE is an early model without the extra crash sensors or airbags.

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GRC50 said:

Looking at the power and ground distribution diagrams it seems F23 blowing would indicate a short circuit in the Airbag Diagnostic Control Module or the wiring as you suggest. ETM pages Y1/3, Y2/10 and Y5/6 refer.

Is it OK to check this circuit with a multimeter, either with or without the battery connected? Could I just plug in a "new" module from a scrap vehicle and see if that cures it? Still nervous of firing a bag ...

Cheers from a sweltering Portugal - shame you're not a bit nearer ...

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