1990 Volvo 240 DL Charging System Problem

[cattledog]

Good job, you're close.

[PaulSimonon]

I went ahead and rechecked it this time with a voltmeter before I started to take the alternator off and had a voltage of 11.6 volts. The last time I was just checking the voltage while still connected (Doh! Sometimes I don't process what I read all of the way before I act on it). Would this lead to a problem?

[cattledog]

I went ahead and rechecked it this time with a voltmeter before I started to take the alternator off and had a voltage of 11.6 volts. The last time I was just checking the voltage while still connected (Doh! Sometimes I don't process what I read all of the way before I act on it). Would this lead to a problem?

Rechecked the voltage? Where are you testing for voltage?
"checking the voltage while still connected"....to what?

[PaulSimonon]

At the D+ terminal. The first time I checked it I didn't disconnect the lead, I just checked at the connector and got battery voltage. This time I actually disconnected the lead from the terminal and retested.

[PaulSimonon]

The alt. tested good. I tested the two leads from the battery to the alternator and got readings of 57.6 kOhms on the wire that runs to the d+ terminal and 0.6 Ohms on the larger gauge wire.

I would assume that this means that the wire running to d+ is faulty and ought to be replaced?

[PaulSimonon]

Also, I am having trouble translating from the wiring diagram to the actual vehicle itself.

My DVOM leads aren't long enough to test for continuity from the Bl-R wire coming out of the fusebox at #13 to the end of the wire going to D+, but there is a connector listed on the schematic between the battery charge lamp and D+ terminal on the alternator. Where is this connector located at in the car?

If the battery charge lamp does not come on despite the alternator not working, would that be a possible culprit?

[PaulSimonon]

I, in my infinite wisdom, just realized that this alternator isn't grounded by the mount to the engine... There was no ground wire on the alternator to begin with, so I just assumed that it was through the mount like many others are. Didn't even think twice about it as I was removing the alternator and saw the rubber in the mount, and apparently I don't read so well sometimes, haha.

There is no obvious terminal on the case that is marked for ground that I can see, it is an aftermarket unit and I have no earthly idea who made it. How should I ground it? Is just running from one of the bolts holding the case together to the frame acceptable?

[billofdurham]

Check the rear plate of the alternator as some have a tapped hole for an earth (ground) lead. If yours hasn't got one then you will need to use one of the bolts. Make sure the wire/strap is heavy enough.

Bill.

[PaulSimonon]

Sorry about the delay all, things have been getting hectic and work on other cars has taken priority for a while. I'm not half bad when it comes to working on other people's stuff, haha.

I grounded the case to the chassis, and got no change.

My next move will be to retest, because I'm 98% sure that somewhere down the line I made a mistake. To me, the combination of all of the results does not make sense which undoubtedly means that I am at fault. If I can't figure it out, it'll go to my local independent Volvo service center which is conveniently located within the limited range of a 240 with a dead alternator.

Happily, my "transmission issue" is not all that serious, the indicator light and the actual gear selection are just off from each other. My center console is cracked and I plan to replace it soon so I'll dig into that issue then. Any inklings?

[PaulSimonon]

I wrapped everything up today on this issue, and it is functioning fine. Changed the ground and all is well. Thank you all for the help.