The insulation on the wires that come from the gray connector on the firewall will crumble and "return to dust" (an environmentally sound fate) on 240s up to the 1988. Unless yours has been rewired or replaced, it is suspect.

Charging begins with a "kick-start" provided through a thin red wire connected to a spade lug on the rear of tha alternator. If that wire is not performing, charging will not begin. The wire can be just "open circuit" or grounded or intermittent, and there are indications other than what you are getting.

Do the warning lights on the dash perform correctly? When you turn the key to Position II, do they all go on? Upon starting do they all go off? There are five (IIRC) : oil, batt, P-brake, Bulb Failure, and brake failure.

The oil light turns off when it looses ground which is inside the oil pressure sensor. The others lose ground because that thin red wire, which provided ground, becomes positive as the alternator begins to charge.

If the lights don't light at all, or just the oil light, that thin red wire is open. If the lights don't go out, the thin red wire is grounded "illegally". In this case, the usual place is in the under-engine-front harness.

This is rather long, maybe more than you need, but I hope you find it helpful. It was to me when my Volvo tech explained it to me.

When you replace the belts, be sure to get a matched set. Just two of the same side is not a matched set. I used only Volvo belts for this application to be sure. Matched set belts are made side-by-side and have exactly the same dimensions and stretching characteristics.


Good Luck,

Bob

:>)