Electrics: Bulb Failure Dipped Beam (but the bulb is fine)

[dgungadoo]

I have a Volvo XC-90, 2004, Manual, 2.4 AWD, 75k Miles.
I'm getting the error message every so often (specially when it's below freezing):

[Bulb Failure Dipped Beam]

...and the right (when facing the car's front end from the outside) dipped light doesn't turn on.
After playing with the on/off switch a couple of times, it sometimes comes on... (so I've deducted that the bulb is obviously not defective)

I'm presuming it's a relay/resistor/shunt that is getting weak, and needs either replacing or re-seating or cleaning.

Anyone knows where I could locate that Relay/Shunt/Resistor on a Right-hand drive XC-90 ?

I don't presume it's the same for the Left and Right dipped beam, is it ?

[dgungadoo]

Attached is a schematic of Daytime running lights from the Volvo Vadis Wiring Diagram (year 2004, TP 3971202) for V70/CX70/V70R/XC90.

AS I understand this diagram, the CEM (Central Electronic Module) has 1 single relay (CMI6 @ 2/152), then it splits to 2 separate fuses 11C/30 and 11C/31. Then through connectors 54/3RB (port 9 & 10)

If the CEM is able to turn on the left dip/daylight running light, but not the right one, through 1 single relay, I deduct that it's not the relay's fault, and something further down the line.

Any idea ?

[pdr944]

hi,
just been reading your post.i have a copy of the same wireing diagram and also have an 04 xc90.looking at the drawing the 30+ FEED passes through fuse 11C/1 and then through CSH4 and then into relay CM17. out of relay CM17 and onto fuses 11B/18 and 11B/17 which are the dip beams.now if you can get the lights to come on sometimes its not fuses.if it was me i would change relay CM17.its possible the relay is faulty as it is carrying a high current constantly because the dip beam lights are on all the time.although the relay may sound like its working (i.e clicking) this does not mean the load bearing contacts are closeing properly.after the fuses the relay is the next weakest link in the circuit.if you go to page 25 of the wireing diagrams you will see the relay board for CM17. this board is located in the drivers footwell above the pedals.it will unclip and drop down into the footwell for repairs although its a bit difficult.i recently had a similar fault on the circuit for the passenger seat motors and it was a relay.if it helps i can send you both these drawings by email highlighting the circuits.

peter.

[dgungadoo]

Originally Posted by pdr944

hi,
(...)i would change relay CM17(...)
peter.

Thanks Peter for the suggestion. Where did you get your relay from, Volvo ?
Do you know if Halfords carries these relays ?

[RoyMacDonald]

Originally Posted by dgungadoo

I have a Volvo XC-90, 2004, Manual, 2.4 AWD, 75k Miles.
I'm getting the error message every so often (specially when it's below freezing):

[Bulb Failure Dipped Beam]

...and the right (when facing the car's front end from the outside) dipped light doesn't turn on.
After playing with the on/off switch a couple of times, it sometimes comes on... (so I've deducted that the bulb is obviously not defective)

I'm presuming it's a relay/resistor/shunt that is getting weak, and needs either replacing or re-seating or cleaning.

Anyone knows where I could locate that Relay/Shunt/Resistor on a Right-hand drive XC-90 ?

I don't presume it's the same for the Left and Right dipped beam, is it ?

Caution advised here...I've had Volvo dip beam bulbs flashing off and on every so often and it's always been a failed bulb. The Volvo bulbs use very strong filaments and they can break but still make contact a lot of the time. Try a new bulb before you go fiddeling with anything else.

Roy

[pdr944]

Originally Posted by dgungadoo

Thanks Peter for the suggestion. Where did you get your relay from, Volvo ?
Do you know if Halfords carries these relays ?

they might do.there are 3 different types of relay on the passenger comp.relay board.CMA 1 TO CMA 4 are normal relays i.e. about 1" square.but relays CMI 1 to CMI 25 are of a smaller size and its one of these that you would need.CSH 1 to CSH 6 are solid state relays they are the long flat ones.breakers yards can be the best place to get them if they prove difficult to find.i was fortunate that the relay i needed was one of the normal type and i had a spare one.

peter.

[dgungadoo]

I took the best part of this afternoon (with a Digital Multimeter) to troubleshoot the circuit, and I'm glad to report that I've found the cause of the problem


The connection box, between the removable headlight unit and the car itself, was flaky. I had to open it, and re-tighten/clean the connection point, and now it's fine.

This may work for you too, if you are noticing that every so often, one of your light bulbs stops working, and you know it's not the bulb itself.

Cheers !

[dlcollett]

I have had a similar problem with a failed day time running light on my 2006 XC90 2.5T. The right running light will not come on, even though I have power at the fuse. I have tested swapping fuses between left and right and it confirms the fuses are OK. I have also swapped bulbs and confirmed the bulbs are OK, even though I bought a new one initially thinking it was just a failed bulb. If I read the wiring diagram right for the 2004 XC90, it appears that power goes from the CEM via a single relay and then to individual fuses for left and right. Assuming the wiring diagram isn't too different between 2004 and 2006, I conclude that if I have power at the fuse, my CEM is not involved in the problem. I will try to disconnect the power connections at the removable light unit and see if I don't have a corroded connection there.

Thanks,
Dave

[dlcollett]

I disconnected the power connection at the removable light unit, and that did not help. I used an electrical tester, and found that there is no power at the connection point on the failed side. I pulled the connection for the side that is working and found power on the relevant pin. I probed the relevant wire on the failed side behind the pin, and still no power.

Can anyone help me? Can anyone tell me if having power at the two fuses for the dipped lights eliminates the CEM as the problem?

Thanks,
Dave

[rustybaby]

Hi,
I'm having a similar problem with my 04 D5. I have the message 'bulb failure dipped beam', when I went to the front of the car to check, I found that BOTH dipped beam lights are out. I thought this is too much of a coincidence (I'm right about this), but I changed both bulbs anyway.

This did not cure the problem. Logically, next thing I checked were the fuses, again, both are fine. After this I have used a 12v tester on the fuse terminals, and there IS power there, then I put my tester on the connector that plugs onto the bulb, and there is NO power there.

Now I am trying to find if anyone knows were I should be looking next.
Now I know that the problem is AFTER the fuses, but BEFORE the bulb connector, but I dont know where to look.
Any help or advice is greatly appreciated.
Regards,
Russ