After my 945 sets for about 2 weeks, the battery will not crank the car. I thought it was the electric antennae motor, so I disconnected it, but it did it again yesterday. I heard a rumor that the radio does this on some 940s. How do I fix this problem?

I haven't worked on the 900 series cars, but if it was my 240 I'd pull the fuses one by one and measure each circuit with an amperemeter to check which one was drawing power with the ignition off.

Best of luck,
Erling.
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I checked for voltage with the ignition off. I got voltage with the fuses out on fuse 1, 2 and 5. 1 is fuel pump and climate control. 2 is Headlamp flasher, central locking, hazard. 5 is clock, audio, courtesy lamps, warning lamps doors, make-up mirror, power antenna.

No other fuses had voltage. What may be pulling my battery down?
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2010 XC90R, XC70, 1993 945.

Hi,

You need to measure the current to try to isolate it. Although, identifying which fuses have voltage with the ignition off is a start. As Leon said, pull each fuse. Get a multimeter with a current measuring function and put it in-line where the fuse was.

This would help identify which circuit it is. Then after that is known, you can look at the schematics to see what is hanging on it and then try to isolate it down to some culprit. Also check to see if anything is spliced into the battery at the plus terminal in case there is something else not stock that is bringing it down. These things can sometimes be pretty tricky to solve.

My 960 battery dies in a month if I don't drive it. I am thinking that it might be an older battery in my case.

Dear Leon,

Hope this finds you well. I just tracked-down a short, that involved fuse #5. The culprit: the overhead light in the passenger compartment (courtesy lamp).

I am sure this was the problem: I put in a spare. It did not blow the fuse. When I re-installed the factory-original unit, the fuse blew. I am not sure what item failed in this unit and may not go further.

I used a few 15 Amp fuses, to check the door-edge lights, the cargo space light, and the blue "warning bell" relay. I left for last the clock, radio, glove box lights, as these are harder to access. The clock seemed an unlikely candidate. I don't use the radio much at all. The glove box light gets only a little "exercise".

In sum, the overhead lights get more use, and so are more likely to fail. I'd start with them.

Hope this helps.

Yours faithfully,

Spook

Regarding the light. Did you mean the light bulb was the faulty part? Or the assembly that has the circuitry and the sockets? Sounds weird for a bulb to do that.

Dear Horatio,

Hope you're well. I didn't bother further to trouble-shoot the light fixture. I put in a salvage yard unit, known good. The fuse didn't blow. I'd guess the problem is on the printed circuit board. I'll re-flow the solder and see if the unit works properly. The bulbs seemed to be in good order.

Hope this helps.

Yours faithfully,

Spook