My 87 240dl's warning lights on the dash flicker after about 15min. of driving. The car drives fine, brakes are ok,etc. Could this be a bad alternator or fuse?
What would cause unrelated warning lights to flicker at the same time. If something was wrong the lights should stay on.
Thanks,
Will

I had the very same problem and now my car won't run. It's probably only a matter of time before the same happens to you. As the owner's manual states, those warning lights are telling you the alternator is not charging. The brake failure etc bulbs (minus the oil pressure light) also come on but that's just the way they are wired.

After a week of these intermittent warnings, usually when accelerating, my car conked yesterday. losing power when the headlights turned on, for example, windshield wipers slowing, then after pulling into the driveway, car died. Following advice in this forum, I first made sure the battery is OK, got it recharged. It started up again. But not for long, I expect.

So I am down to a wiring/alternator issue that I don't know how to solve. Don't know what to advise you except don't go for long drives til it's fixed.

Cal

And the other thing that's going on when those warning lights light up with the engine running is that the alternator is prevented from making electricity.

That thin red wire, the one that's the ground side for the warning lights, provides the low amount of voltage to the alternator rotor that creates the rotating magnetic field. Wire grounded causes the lights to come on and also means no magnetic field so no charging.

Also, to work the alternator must be grounded to the block. The bracket has rubber bushes, there is a ground wire.

Charge up the battery, it'll run in daylight for a while. Then assume that the thin red wire is compromised. Put in a work-around wire.

Good Luck,

Bob

:>)

There are two possiblities I can think of.

(1) The alternator brushes are about worn out. The brush/regulator unit can be removed and checked in situ. If the brushes are under 5mm long, replace them. The total unit is about $80 from a dealer, I have never checked for aftermarket availability. As an electrical part, it will be non-returnable if it turns out that you don't need it. The brushes alone can be replaced and are available from the Parts Bin. Takes some skill with a soldering iron.

(2) The wire that connects the ground side of all those flickering warning lights to the D+/61 spade lug terminal on the alternator is grounding intermittently. That circuit grounds through the brushes so that when the alternator begins to charge the ground is lost and the lights go out. The oil pressure light is separate.

Look at the wires exiting from the harness behind the alternator. The fat red one is not usually damaged. The other two, red to D+/61 on the alternator and black to the oil pressure sender, frequently suffer from failing insulation. Very Visible.

As long as the bare spots don't touch anything, no problems. I have replaced those two wires on every 240 I have ever owned. The under-the-engine routing is fraught with heat, oil, road crud, and dry-out which, when combined with the Volvo hare-brained idea about environmentally friendly insulation, damn near guarantees failure for 1983 thru 1988. Volvo fixed the problem in 1989. Sorry.

Run new wires from their respective user terminals to the gray connector on the firewall, routed along the fenders. Just leave the old wires isolated.

Good Luck,

Bob

:>)

Great post, my 91 does something similar for a few seconds after start up occasionally, cleaned the battery terminals , that helped for a while, alternator has 141k on it so it could be the brushes, when it does happen, the lights will go out if one ups the engine RPM slightly, and as you said the oil light is seperate. Thanks.