hello, my 1980 volvo 240dl's alternator is kaput, i think, the battery dies if i drive with the lights on, with the engine running. if i disconnect the ground from the battery the engine dies like i turned the key off, this is my alternator right? can i just remove it and replace the regulator/brushes, or is it more extensive? the alternator is turning fine from the belt, and i dont have any dash lights on, however when i turn the ignition on and do a bulb check my amp light and oil light do not illuminate.

thanks guys

 

the amp bulb is required for the alternator to kickstart itself. so if that light is burned out, or not wired properly, the alternator won't charge the battery even fi its a perfectyl good brand new battery.

so, I'd check that bulb first. its connected to a thin red(?) wire to D+ on the back of the alternator, if you GROUND this wire with the ignition switched on (and a charged battery), the dashboard light should light. if it doesn't, A) check the bulb, if its OK, B) check the wiring.

 

hey thanks for the fast reply! i had just come to the same conclusion from reading around on this forum, there is a small black wire that isnt connected to anything, but i can see it was connected to the little sensor next to the oil filter, im assuming thats a low oil sensor right?

is there any fuzes that control the dash lights? when i do a bulb check my oil light and amp light are not working, could a fuze be doing this? or are both bulbs burnt out, how do i replace those light bulbs? do i just pull the dash apart? thanks again, your really a big help

 

the sensor near the oil filter is the oil PRESSURE sensor, not oil level.

if you remove the kick panel(s) under the drivers side of the dashboard, you should be able to reach up under there and get to the bulbs, its a bit of a contortion act. dunno if a early 1980 is any harder or easier than the later 240's I'm familiar with. I find using a led head-light and a inspection mirror on a stalk can really help in these situations. run the drivers seat all the way back, so you can get under the dash on your back...

 

ok im going to ground out the small red wire, like you said, and turn on the ignition, and look for the bulb to light up, if it doesnt i will remove the bulb and see if its burnt out,

thanks il let you know how i make out

 

wow that was fast, pierce you genius you!

i looked at my little red wire, it wasnt connected to anything, just dangling, i grounded it out and BAM! amp light lit up like a christmas tree!

so hopefully i wont be needing an alternator rebuild!,

one last thing if you dont mind,

where do i re connect this small red wire too? i dont see any obvious spots

thanks yet again

 

hey maybe you can help me out some more, on the back of the alternator i found a plug with no wire, it is the only connector on the back and its right beside the thick red wire, i put a new pin on the amp light wire and connected it to the alternator, started it up
and now if i disconnect the batteries ground wire the engine keeps running! it didnt before, so the alternator is working, here is where it gets sketchy, the amp light stays on, it doesnt go out, also the break failure lights and the parking break light stay on, if i turn the pbreak off the light dims a bit but still stays on, so break failure light,pbreak light, and the amp light all stay on. they are dim, but on, what can i check? at least the alternator is working now,

 

a bosch alternator has a big B+ pin for the fat red wire that goes to the battery (via the starter motor), and a smaller D+ pin for this thin red wire to the alternator light, then there's the ground terminal.

I've never used a ac/delco in a volvo so no idea.

do you have a voltmeter?

charge your battery with a standard car battery charger til its fully charged. disconnect the battery charger, and let the battery sit at least an hour. the voltage across the battery should be around 12.6V or something now (lower if its very cold out). start the car, and it should be 13.8V or something. (about 1.2V higher then the resting voltage, give or take a few tenths) ... if it is, then everything is working.

 

the b+ or the large red wire is on a threaded rod with bolts holding it down, and another grey wire down the post, the amp light wire i plugged into a male slot connector just below the b+ post, i will get a volt meter on it tomorrow, but the alternator is working now for sure,


i just dont know why the [break failure] light and the parking break lights stay on half illumination, have you seen this before? the amp light stays on after i start the car, but at half brightness, if i pull the pbreak the light is very bright, but when i put the pbreak down, the light gets dimmer but it stays on at half power, same with the other 2 dash lights

 

I haven't dug into anything as old as a 1980... but hmm. greenbook

so, the instrument cluster page shows fuse 13 goes to the cluster via the half-round connector 32/2, and all the indicator lights are connected to that.

hmm. fuses. this car is over 30 years old. I would replace ALL the fuses with brass/copper german fuses, like these ... Mercedes Ceramic Fuse Set 8-16-25 AMP Set NEW GERMAN on eBay!



the crummy tin Buss fuses sold in most car parts stores are junk and only last a couple years before they rot away.

clean the fuse holder contacts with a pink pencil eraser