My 82 245 with LH-Jetronic after a few minutes of running blows 8 amp fuse 12, which according to Volvo official service manual goes indirectly to ECU. (Has also blown a 16 amp fuse when I substituted it.) Manual shows the wire goes from the fuse to the coil or the ac relay, then to ECU terminal 20 through a blue-yellow wire. No blue-yellow wire comes off the coil, so it must come off the relay, which according to my Haynes manual, seems to be behind the center console covering the radio. So I guess the next step is to find that relay, see if there's a blue-yellow wire coming from it,maybe buy a short detector (avail from JC Whitney) see if that is drawing too many amps. If not there, then try to find worn-off insulation in the wiring harness behind the dash (seems unlikely). I have driven the car 20 miles by running a jumper wire across the fuse 12 terminals. Didn't blow anything, seems risky though. I have checked fuel system electronics with test light, following the Volvo official manual, everything checks out OK.

I also ordered the official Volvo wiring manual.

If anyone has any hints, I'd appreciate receiving them. Thanks very much.

Jon

 

Bump for knowledge?

 

It looks like it powers the back-up lights (manual only???), power windows, driver seat heater, and air conditioning.

 

Thanks, I overlooked that. Car has no heated seat or power windows, but I just found out my backup lights don't work, therefore it looks like that's the first circuit to check with my short detector, which is available from local auto parts store, made by KD Tools, about same price as JC Whitney