Dipped light intermittent

kc66

On an 01 Volvo S40- when I turn the ignition one of the lights sometimes doesn't come on. If it doesn't come on it usually comes on at some stage during my journey. If it does come on it doesn't go off until I switch it off so it doesnt seem to be a lose connection. I have tried fiddling with the connection and it made no difference. There does not seem to be any pattern as to what makes it switch on. Any idea what is causing this? Thanks in advance.

Bruthal

kc66 wrote: »

On an 01 Volvo S40- when I turn the ignition one of the lights sometimes doesn't come on. If it doesn't come on it usually comes on at some stage during my journey. If it does come on it doesn't go off until I switch it off so it doesnt seem to be a lose connection. I have tried fiddling with the connection and it made no difference. There does not seem to be any pattern as to what makes it switch on. Any idea what is causing this? Thanks in advance.

That would not show it is not a loose connection. The circuit is opening somewhere, and re closing, usually a bad or loose connection is the cause, or a damaged wire.

Where did you fiddle with the connection, at the bulb itself? If there is a relay for the headlights, it might be worth plugging it out and back in. There is an electronics module in them that probably controls the headlights which could also be the location of the problem.

kc66

robbie7730 wrote: »

That would not show it is not a loose connection. The circuit is opening somewhere, and re closing, usually a bad or loose connection is the cause, or a damaged wire.

Where did you fiddle with the connection, at the bulb itself? If there is a relay for the headlights, it might be worth plugging it out and back in.

Yes at the bulb. Do you know where the relay is located? Is it with the fuses? Thanks.

Bruthal

kc66 wrote: »

Yes at the bulb. Do you know where the relay is located? Is it with the fuses? Thanks.

It could be a problem with the central electronics module anyway which would have the relays on its circuit board, which controls the lights in that car. Im not sure of the location of it.

It would mean that the correct terminals on the connector plug can be connected to 12v+ to test if thats the problem, a bit more tricky to prove on an intermittent fault though.

tossy

Are the xenons or halogen? If Xenon it's most likely an igniter problem pretty common on alot of OE Xenons,when it doesn't come on first try flicking lights on and off a few times to see if you can get it to fire up.

I've had similar problems on 2 cars one an Audi and one a VW,for both cars the igniter wasn't available seperately as a part from VAg so i just put up with it,the never failed to ignite after a few on'off flicks anyway and once ignited the will never go off again unless you turn them off.

Bruthal

tossy wrote: »

Are the xenons or halogen? If Xenon it's most likely an igniter problem pretty common on alot of OE Xenons,when it doesn't come on first try flicking lights on and off a few times to see if you can get it to fire up.

I've had similar problems on 2 cars one an Audi and one a VW,for both cars the igniter wasn't available seperately as a part from VAg so i just put up with it,the never failed to ignite after a few on'off flicks anyway and once ignited the will never go odd again unless you turn them off.

Good chance its that alright, especially if it never goes off once its on which does go against the loose connection probability alright.

Nissan doctor

Start with the basic first, when a bulb starts to fail it can often come on and off intermittently.

Bruthal

Swap the bulbs around to test that one.

Nissan doctor

robbie7730 wrote: »

Swap the bulbs around to test that one.

Or just replace it, they are only a few euro.


If your swapping bulbs around make sure not to touch the glass.

kc66

They are halogen lights. Ill stick a new one in.

Nissan doctor

kc66 wrote: »

They are halogen lights. Ill stick a new one in.

That's just a standard car bulb so should be no more then €5 max, depending on brand, in a motorfactors. Halfords will be much more expensive.

coppercat

almost certainly a fault in the central electronic module ,it's a common fault on these. i would check the bulbs first just to rule them out but they are probably ok . there are 2 relays that control the dip beams ( one for each side ) inside the CEM that burn out . the CEM is located under the dash by the drivers right knee . its a grey box about 8" x 4" .if you are handy with a soldering iron you can replace the relay or just pick up a 2nd hand CEM from a scrappy , it'll just plug and play no programming required !

kc66

After a bit of research online and previous comments it looks pretty likely to be the CEM. Some good information here. Might try getting a relay and soldering it. Not much soldering experience but if I screw it up I will get a replacement CEM

Bruthal

kc66 wrote: »

After a bit of research online and previous comments it looks pretty likely to be the CEM. Some good information here. Might try getting a relay and soldering it. Not much soldering experience but if I screw it up I will get a replacement CEM

Try simply plugging the leads out of the cem and back in first, and see how that goes. It may be one of the pins not making a great connection.

coppercat

good luck with the soldering take your time and try not to apply too much heat to the board as the pins in the relay are quite small

Bruthal

If the relay contacts themselves are the problem, as in they are closing but are gone bad, there will be obvious signs of overheating on the relay when you remove the cem cover.

If the relay not closing is the problem, then its likely a problem with the cem circuit board circuit to the relay coil, or a connection problem in the plugs that plug into the cem.

Its a bad design having relays you cant plug out imo.

kc66

It has not happened the last 7 or 8 times I started the car.