i have a 1987 SW 760 4 cyl. turbo with a short which has been happened on three different times. it is on the same circuit each time ,fuse no. 9 (15a) which includes the air cond.,the turn signals, heater fan,power seat. i have moved the wires around comming out of the fuse harness and this has fixed the problem in the past but there is a short somewhere. i have disconnected the air cond. compressor turned off the turn signals, and the heater and the fuse still blows as soon as i turn the ign. key on. does anyone have a system to troubleshoot this and repair the problem?

Fuse 9 also powers the seat belt reminder tome. Pull this box from the relay tray, back row, second from the left. It has a small speaker in it with some slots. Try it again.

Disconnect the seat heater connections. They are under the two outer caps by the seat track ends. Remove the screws, pop the caps off and unplug the connectors. Make sure the seat is all the way back, if possible.

Disconnect the A/C relay under the dash behind the glove box. It is powered by fuse 9. It's rectangular with white-blue, black, yellow, yellow black wires to the connector. This is from the electrical manual for the '86 740/760 models.

I'm just suggesting different options.

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Warren Bain - '86 744Ti M46 >285Kmi, '96 965 >99Kmi Wifemobile near Manassas Va.. I get e-mail replies to my postings.

I don't know if this will help or not but I hope so.......
I have a VOLVO wiring manual for my 89, I know your car is an 87 but it may be somewhat the same in wiring...

Fuse 9 in the book mentions it is responsible for:
things to look at and check are in double parenthesis:

Turn signals ((flasher relay, fuse 10 and 2 lines, wiring to side marker,turn lights))

Air conditioning (Auto Climate Control) ((solenoid for AC compensation,fuses 10 and 16 lines, control panel, in car temp sensor,fan and delay relay, heater fan temp sensor)) there's a bit more sensors Under passenger dash too many to list))
Seatbelt reminder (USA,CDN)

Power windows, Electric cooling fan ((fuse 7,8,10; power window relay (same one that goes to electric fan), window switch lines,electric fan thermal switch,electric fan lines))

Heater fan ((fuse 16, heater fan resistor, climate control panel, motor itself))

Electrically heated front seats ((fuse 6, seat thermostat, heater pads, heater switches, passenger seat contact))

Hot start valve ((???))

Basically look over this and see what you have and check the wiring to it and make sure it is grounded CORRECTLY and not frayed touching the chassis........Again hope this helps! :-)

I spent several days myself looking for a source to a blown fuse. There is a device called a short detector which if I had one would probably taken me less than 30 minutes. They are not that expensive, below 40.00 probably. Someone out there maybe can recommend one. Good luck.