Hi everyone, I'm new here. I recently purchased a 1991 240 wagon and the electrics are driving me nuts. My headlights are stuck on high beam, the driver side rear running lights don't work and the driver side rear turn signal doesn't work. The fuses are good and it has all new lightbulbs. I've cleaned the relay under the hood. The rear driver side brake lights do work and the front driver side turn signal has a rapid blink. Help!

 

diagnosing that will require some electrical troubleshooting with a volt meter, and probably a helper from time to time.

my wiring diagrams for a 1991 240 are US specific, as there are often subtle differences in international models.

unplug the 'step relay' for the headlights. hook your meter up in 'volts' mode between socket pin 31B (brown wire) and 15 (red wire, also blue wire that goes to 81A). have friend pull the high beam stalk back and release every couple seconds, when they click it you should see +12V, 0V when they click it again. if its always 12V, then the highbeam switch in the steering column is bad, or the wiring is bad. if it toggles with the high beam stalk, then odds are the step relay is bad.

for that left rear turn signal issue, hook the volt meter up to the 'blue-green' wire to the left rear light cluster, and the black wire (ground). you should see +12V blinking on/off there at the rate the lights are blinking. if you do NOT see it, the problem is in the wiring, if you DO see blinking 12V, you either have a bad bulb or a bad socket in the tail light assembly. try gently cleaning the contacts on the bulb holder and the flexi-circuit board on the light assembly, using a soft pink pencil eraser.

 

have a look with a flashlight where the bulb holders touch that plastic film for the tail lights. often the traces get damaged. it's a weak point. cleaning with pencil eraser is a good idea. make sure you use the correct bulbs if you replace them and replace in pairs if you can, volvos compare the current draw of left to current on the right and if it's not the same you ll get the bulb failure light on. check any black wires that connect to your light wiring , you will find a ground on the inner fender near each headlight and a ground near each tail light. unscrew them and clean the black wires and the body and screw and replace to make sure you have good grounds. clean the contacts on the bulbs themselves or install new bulbs. make sure they are the right bulb and not just one that fits,, you can melt the lenses easily by having the wrong bulbs or if you somehow manage to get the bulbs installed backwards. If you are parked in front of a glass window of a store you can often use that as a mirror to inspect them yourself.

if the bulb holders are blackened , sometimes they don't make good contact and then heat up so they could be less springy or that can damage those fragile traces

if the signal light flasher relay speeds up, it likely means the relay has bad contacts, replace it, it's probably a cheap part. it's probably near the drivers feet. turn the signals on and listen for it and you'll find it that way. It might be the same part as the hazard lights relay, sometimes you can switch them for the interim while you get a new one. just see if the plug connector looks the same. it probably only has two or three terminals.

 

no, fast flash means either the front or rear turn signal on that side bulb is out (or an open connection)... there are no bulb detects on the turn signals since they don't turn on together. the 'replace both bulbs' is very good advise for the brake and parking lights, however.

I suspect its either the rear turn bulb, or its the fixture/socket. a ground problem would affect the other bulbs on the same side too.

I put a little bit of DeOxit on my lamp connections, after gently cleaning them.

 

I stand corrected, Yes the bulb failure doesn't cover the signal lights, good point!

correct me if I am wrong but I think the flasher relay uses a bi-metallic strip, the current heats it up , then it opens,in turn opening the relay and then the bi metallic strip cools and closes, closing the relay. excessive current might cause it to heat up faster , increasing the frequency? I might be off on that..but I think the relays are common to most cars. sometimes they go faster when they wear out. a bad bulb contact or bad ground could cause higher current in the bulb circuit due to increased resistance of a bad contact. bad contact in the relay itself could also increase the resistance, in turn raising the current and causing the strip to bend faster, thus increasing the frequency of the flashing.

thinking that through more then why would the bi metallic strip's current change with different loads? (if it is in turn just opening and closing the relay contacts) well some of them have two connections and some have three so maybe that's what the third connection does, it can work in series with the bi metallic strip or the third wire might supply power just for the bi metallic strip so it didn't fluctuate so much with different current loads?

some of them are louder.. I like to be able to hear them so I know if I'm still signalling without looking for the dash indicator so I find myself in the auto store looking for cheap ones that are noisy ;-)

Ive always just grabbed one and used it as long as the prongs are the same, they seem to work but here are probably some current ratings. I changed my trailer to LED signals so I don't have a brown out when I tow it with my 122,

I tried using LED tail light bulbs in my 240, they work I guess but the bulbs are bigger physically. i also noticed that there is a lens that is never used so I added a pair of brake lights in there because they always seem to be on the blink ;-) I'm not sure my bulb failure system liked that too much. Ive been thinking about clipping the wire to the dash light.. it's great when the car is new and after that it seems to be as much of an annoyance as a help. It's tempting to try just removing the tail light assemblies completely and replacing with sealed LED units. a lot of times the lights themselves start filling with water too.. we get a lot of rain here.

the rain runs down in around the outside of the trunk seal and drains near the tail lights. once they arent; new and sealed too well the problems of water getting in get worse. I just noticed one of the tail lights on my 740 is half fill of water. maybe it needs a drain hole.

what I ended up doing on my 240 was I took all the factory sockets and the plastic film strip out, then I made plastic washers to fit standard bulb sockets. each bulb has two plastic washers, one is glued to the light assembly the other is glued to the socket, then I just poked holes through both washers with a hot pin and used twist ties like you use on plastic bags to hold them so If I want to change a bulb I remove the twist ties and I can take the bulb socket out with it's washer glued to it.. then with normal wiring connections on the bulb sockets I hard wired it together, no more issues with bad bulb contacts on the plastic film strip. it also made it so it's hard to replace the plastic covers inside the trunk as they stick out a little to far.

 

nah, they USED to use bimetal strip things but the ones in these volvos are electronic timed, they are designed to detect a bulb out and blink really fast.

 

Sam,good advice from previous posters, but one more thing regarding the rear lights on your 245. The plastic base to the tail/stop/side marker and reverse tends to melt when it gets hot( think warm weather, nightime with the brakes on sitting at a long light) When this happens, the contacts of the bulb holders may need to be bent or have a conductive shim carefully placed to regain contact. If too far melted, replace the light assembly. Aftermarket has filled in the gap in supply for new ones recently, and will last a few years.

 

you gave me something to go on ! 940 front signal not working, good bulb
8/14/2022 Front passenger signal light not working, bulb is good ~ problem solved !
It was wire in the plastic socket, needed some TLC, it's working again (it was simple)

 

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