no need for new harness,check&clean all the grounds at the 4 corners

You sound like me.

When my son bought his first car ($200) Not a Volvo. We had a friend tow it home and I said "Mark, this may be your car but it's also your Classroom."

He bought it knowing all the obvious issues. But at 39 years old, this old Mopar has been the best Shop class money could buy, well worth the $200 for the 'course'. He's put over 11K miles on it in two years and he is pretty tuned into hearing warning signals of problems.

Good luck with your new schooling tool.
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'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.no.net/ebrox/Tony's%20cars.htm

if you are near Denver there is an 83 or 84 in the junk yard at 60th and Federal that has a new wiring harness...usually $20-30 or sometimes they don't even charge for hand full of wires

That is not the engine harness I will bet.

One of two problems most likely and both are easy to check. First take an ohmmeter and measure the little red wire on the back of the Alt to the engine block. If that is zero ohms' that is what you need to fix. Fastest way to fix that is to locate the big gray connector in the center of the firewall. There are four wires and most likely they are a mess. The Red one goes to the Alt, the black to the oil pressure sending unit just behind the alt, the yellow blue goes to the starter, and the yellow to the water temp sensor located under the intake manifold. You can chop off the red wire on the passengers side and splice a new on on. Run it down the passengers side along the harness already there, and then over to the Alt. I would just chop off the old red wire and leave it alone, or grab on and pull it out of there. I replaced the entire gray connector with a trailer light connection. Less than $5, and the wires are long enough to reach the starter and the H2O temp sensor without doing a splice. That type connector is sealed, the wires will not degrade and is it easy to do. The wire colors do not match up, but who cares.

If little red wire is not shorted to chassis, measure from the alternator chassis to the engine block. That should be zero ohms. If not solid zero ohms you need to replace the ground wire located on the bottom side of the alt. Go with at least a 14 gauge wire when you do it. Without the ground the system will not charge. Clean both places the crimp lugs go, get a good solid connection.

Now if you need a replacement harness I have on that came out of my 86. There were only four wires bad, but I replaced the whole thing before I knew that. Stiff, oily, but still good. Minus the gray connector harness of course. Post back later if you still think you need one.

Regards,

Paul

I finished doing mine about a year ago... further inspection revealed only 5 bad wires... the five that go to or from the gray plug... may or may not be the case with your sons car, but... maybe. Had I known then what I found later, I'd have just replaced those five wires...

That red wire to the alternator is indeed one of the offending wires. The link below is a brief page I made of the harness dissection..

http://otherpower.com/mattb/volvo240wiring.html


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-Matt I ♥ my ♂

Hi,


I revived my decayed and dilapidated engine harness which I bought half burned from the salvage yard. It took three spools of marine rated wire, various pieces of plastic looming, and neoprene heat-shrink tubing. The lead solder was quite inebriating. I should have worn a paper mask.

I enjoyed the result, but would not return to the task again.

Is the lamp "Battery" lit while the ignition key is in the "On" position? You should check the gray plastic rectangular firewall connector. Pin "#3" a red wire, lights the lamp via an internal ground inside of the alternator voltage regulator.

If the red D+ wire becomes severed, the alternator will fail to charge. I would route and fit a new wire in the interim of a wiring harness purchase and installation.


Goatman