I've "rebuild" the wiring harness on both my 240 cars. First, don't scrap the existing harness. I've found only some of the wires needed replacement - not all of them. Typically, the wiring to the oil pressure and temp gage sending units and the wire from the alternate to the warning light need replacement. The Bosch FI wiring was fine in both my cars, as was the cable from the alt. to the starter motor. On my Turbo, the insulation on the wiring from the firewall connector to the fuel pump relay and ECUs on the passenger side was burned away - I used good wires from another Turbo here. Here's how I fixed them:

1. clean engine, label all harness connections (including ground) and carefully disconnect all wiring from the engine and from the two connectors at the firewall. You might even make a few photos/sketches where it runs through the intake manifold runners.

2. strip/cut off all the harness plastic.

3. clean wires, lay them out on your work bench and resistance test all wires that look salvageable

4. replace any bad wires (here I visited the junkyard for wiring from the INTERIOR of late model RWD Volvos - same gage/colors/connectors and hadn't been exposed to engine compartment heat.

5. make a wire loom using split cables from RadioShack

6. go slow and check and recheck all connections before turning on the current.

These repairs have worked fine for more than 4 years on the Turbo and 3 years on the DL. Hope this information helps.

1)Get spools of various colors and try to match the Volvo colors as closely as you can. Get new female connectors.

2)Solder your connections and use heat-shrink tubing on the soldered joints.

3) Remove the intake manifold to give you more room for your hands. Replace with a new gasket. (and do the flame trap while it's sitting *right there out in the open*!)

4) Bag the under-the-crankshaft location for the harness. It's far preferable to come out to the fenders and up and across the firewall. I only left the big fat wire from the alternator to the starter to pass under the crankshaft pulley.

5) Wrap your new harness in the split loom sheathing. It keeps your new wires neat and clean.

6) Before you start disconnecting the old harness, wrap a masking tape label on each wire near its connection indicating its function or connection. That way you won't get lost in a rat's nest of wires.

7) The old plastic sheathing will probably be rock hard. I ended up needing to break off pieces -- it just wouldn't cut.

Give yourself one busy day or, preferably, two relaxed days so you can enjoy yourself as you do the job.

Rob