1986 Volvo 240 alternator wiring

[atikovi]

I'm replacing some wires in a 1986 240 and I'm not too familiar how this circuit works but there is supposed to be this small red wire from the alternator to the battery light in the instrument cluster.

That looks like it's connected to the alternator housing through bolt, and so it's to ground. Is that correct? Alternator also has too unused terminals marked W and D+. No wires go there?

 

[GSCJR]

Your current cable arrangement is incorrect. The B+ cable (thick) should be coming from your starter motor to provide power, and your D+ cable (thinner) is for your dash light, no other connections are required. Hope this helps, good luck!

 

[wings&wheels]

Your current cable arrangement is incorrect. The B+ cable (thick) should be coming from your starter motor to provide power, and your D+ cable (thinner) is for your dash light, no other connections are required. Hope this helps, good luck!

If the Bosch type alternator has rubber bushed mounts, appears to, wont it also need a ground wire?

 

[GSCJR]

Possibly, it's been awhile since I've worked on one. A ground strap may be necessary once the two cables I previoulsy mentioned are corrected.

 

[wings&wheels]

Possibly, it's been awhile since I've worked on one. A ground strap may be necessary once the two cables I previoulsy mentioned are corrected.

..ask me how i learned this

 

[atikovi]

Your current cable arrangement is incorrect. The B+ cable (thick) should be coming from your starter motor to provide power,

B+ goes to the battery. The actual cable to the starter is much thicker. I connected the D+ to the dash light circuit and got it go illuminate, but it stays on while running and I get just 11.8 volts output. Might have to run a grounding wire to the alternator as it shows 26 ohms resistance to ground.

 

[mk378]

The black wire on the frame bolt is the ground. The voltage between the alternator case and battery - should be close to zero both off and while running. If there is a voltage difference, check the ground circuit.

The light wire should be plugged onto the smaller insulated terminal near the output terminal (note the flat push on adapter). You haven't found that yet. The black box and wire near D+ looks like a noise filter capacitor, leave that in place. I think "W" is an AC output for diesel applications that have a tachometer run by alternator rpm.

 

[atikovi]

The voltage between the alternator case and battery - should be close to zero both off and while running. If there is a voltage difference, check the ground circuit.

Odd that it has that resistance while running, but assume the alternator is bad and something internal is causing it.

 

[GSCJR]

B+ goes to the battery. The actual cable to the starter is much thicker. I connected the D+ to the dash light circuit and got it go illuminate, but it stays on while running and I get just 11.8 volts output. Might have to run a grounding wire to the alternator as it shows 26 ohms resistance to ground.

Okay , now try a ground cable to the alternator case to see if it will improve things.

 

[atikovi]

I ran a jumper direct from the battery to the alternator case and still the same thing.