I am now almost finished bringing back a friend's old '86 sedan from the "driveway death" and had run into some very vexxing electrical problems.

It began as battery discharge and very low voltage w/ no voltage light illuminating.

Checked Alt, replaced brushes/regulator. Cleaned where brushes ride in alt.
Hooked alt back up, tensioned belts properly.

Result: Getting more consistent voltage---14.4V or thereabouts from exciter post on alt.
Batt light on faintly, more light at low RPM, less at high RPM--that's expected.
Voltage at the alt. post of fat red wire running to starter however, was ridiculously high--about 25V. I checked and rechecked....same readings (I was looking at right markings on my analog meter.) I'm thinking alt. is toast--but have doubts about that.
Voltage at post on starter where fat red wire from alt. connects to only 12V. Weird....
Voltage between batt. posts is also 12V. OK---maybe batt. is problem...(tested in good '90 245 and battery is fine as readings are a hair under 14V.)

Of course, all who have dealt with these gremlins know that they cause the strangest things to happen in the electrical system....The most irritating: OD on m46 cutting in/out, or not engaging at all even when the "5" light in the cluster is constantly illuminated (BTW--took the time to check the solenoid, all wires to it, checked relay, checked switch, blah, blah...all to find they were all good).

Began to run circuit component tests. Load tests of 14V good on all wires in charging system. Cleaned all contacts.
Replaced + & - batt. term cables (they were horrible anyway).
Checked all grounds and they were good.

Now--I'm two weeks into this stupid project on just the electrical problem and I'm sounding more and more like a sailor when I'm out in the driveway and the neighbors give me strange looks.

I've taken the car out on test runs--some around the block, some for 50 miles and haven't drained the batt, but still suffer from the weird side effects of the problem....

Then, while test driving one day, batt. light suddenly goes off...OD works, horn now sounds at correct volume & tone, stereo doesn't keep shutting off & turning on...etc. (I'm thinking..."help from above?")....but, after about 1/2 hour more driving, batt light back on...same symptoms again....Road Rage hardcore.

Ok--so I take the alt. out and test it at the local autozone. It's just fine...so I have them test it a few more times....still fine. (Wasted more time and cut my forearm and knuckles in the process)

Put Alt back in....now I'm thinking I'm going to have to pull the harness from under the front of the oil pan and inspect....(hurray!)

However--after I get the alt back in and am testing voltage just for kicks, my hand lightly bumps the loop connector of the fat red wire and I see a spark jump INSIDE of the connector housing--the little area that you can see between the insulation and actual connector.

Immediately the car's idle drops/jumps/settles back when this happens. Oooh, look, now my voltage is about 14V at both terminals on the Alt, basically same at batt. & BATT light off on cluster. (Now's where I start swearing, but not at the car, but at myself)

I repeat bumping/jiggleing the wire right at the contact...same results... Great, now I can at least replicate prob/fix.

Turn off car, disconnect fat red wire...It turns out that the connection between where the ring part of the connector and the butt side of the connector are pressed together (BTW--what a dumb idea for terminal connector design instead of one piece)has corroded and there is intermittent separation, causing the spark and all my voltage woes.

I play a bit with the connector and it easily breaks in two....Now, how come this didn't happen the last half dozen times I've handled that wire and when I inspected it?

Replaced connector---All's Copacetic.

So, I guess the moral of the story is....sometimes you have bad luck, good luck, and need to inspect things more closely when it comes to electrical problems on 21y.o. Volvos.

Upside: Learned a whole lot about the entire wiring/circuits in the car because of all the phantom problems!

Downside: Now my buddies who are also into the 240's are asking me to look at their electrical problems. My answer: Look at the Brickboard....educate yourself, try troubleshooting.....then if all fails, I'll look but I'm not promising anything!

Sounds so much like my electrical follies with my son's car. Battery would discharge. We would work on it and I would think we had the problem fixed with good voltage readings only to get a call a day later that the bat was dead. This happened multiple times. Turned out to be the ground wire was corroded. When I'd bump it working down there it would work for a bit. Intermitent is frustrating.
--
1980 240 328k 20 years.

"Voltage at post on starter where fat red wire from alt. connects to only 12V. Weird...."
Exactly. You noticed that something was wrong, in that the voltage at the alt was 25v but following the wire to its other end showed 12v. Something wrong with the wire or connection.
--
1980 245 Canadian B21A with SU carb and M46 trans in Brampton, Ont.

Electrical problem chasing/solving is my worst challenge. Glad you solved your problem.

I recently had a new 88 240 enter my life and traced an intermittant (that became constant) no start to corrosion that had formed on the red wire leading to the underhood fuse. It was built up in the connector as you describe as well as isolating the connector to the positive post connection (although it appeared perfectly clean). Finally traced it down by finding an wire run from the battery to the fuel injection relay would bypass the problem.

Give me a mechanical problem any day compared to one electrical in nature.

Randy

Hey Randy -

When I went to check that 25-amp fuseholder on my 1986 the blasted thing crunched into 4 or 5 pieces. Now what??

The connections went like this. Inside the fuseholder are two separate pieces of metal that are a female spade lug place for the fuse to poke into, and a male spade lug on the other end where a red wire pokes onto. Each red wire has an end piece like a female spade lug. Bottom line is that the fuse can be stuck into the female ends that are crimped onto the wire from the battery and the wire to the fuel relay.

So I threw away the remaning bits of fuseholder, and stuck the fuse directly into the two red wires. I re-did it later so that the longer of the two red wires sort of wove in and out of the other nearby wires so the bare ends would not wander about and short out on something.

Worked for the 6 months that passed while diddled with other more pressing repairs.

Yeah, I know you fixed it correctly, so this is a future reference thing.

Regards,

Bob

:>)

One of the first things I do when a 240 Volvo follows me home is to replace the fuse holder. At this point in their life they are extremely brittle and corroded.

Most of the auto supply stores carry new holders that have a "weather proof" cap that snaps in place over the fuse. I put a layer of dielectric grease on the fuse and I have had no trouble with the replacements.

On the 88 I was referring to I had replaced the fuse holder and assumed it was the problem but it turned out to be the problem of hidden corrosion at other places along that same wire. Any connection associated with the battery or close to it is suspect.

It is easy to forget that these cars are 20 years old and so many of them suffer from lack of proper maintenance. Another standard procedure of mine with newly acquired cars is to remove and clean/dielectric grease every electrical connection associated with the fuel injection system (except the O2 sensor)and I think it has helped foil intermittant gremlins.

Randy