I have a 1988 volvo 740 and my low beams and front turn signals stopped working. All fuses are good as far as i can tell and i put in a new headlight relay.And they are still not working relay is clicking when i turn on the lights. All suggestions welcome.
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
Most common problem is burned connectors at the relay that switches from high to low beams. I think that in '86, the relay was still inside the car above the driver's left foot. If not there, it is toward the front of the passenger compartment on the driver side, between the front inner fender and the battery. If it clicks when you move the dimmer switch, you can follow the click to find it. If the wires are good, the relay contacts may have failed.
On my '91, I lost the low beams because the headlight circuit in the bulb failure sensor had failed. The bulb failure sensor was an orange can-shaped device directly below the steering column under the dash. The headlight low beam wires were gray, as I recall. A new sensor was $150, so I cut the wires and bypassed it. I figured I could tell if I had a low beam burned out. I did not need a warning light for that. The bulb failure sensor still worked for the tail lights.
There is a relay that controls the headlights, volvo calls it a step relay. You will have to check that power is getting to this relay. If not, check all fuses and wiring. If power supply checks out ok, you may have to replace the relay. Let me know if you need any more info or a wiring diagram.
For Audi A4 the fuse box is located on the left side of dashboard behind a plastic cover (for left hand steering wheel vehicle). On inner face of the plastic cover you will find the fuse diagram. First fuse on first row from left upper corner is Fuse Nr.20 = F20 (15A) - RH headlamp low beam, headlamp adjustment. First fuse on second row from left upper corner is Fuse Nr.21 = F21 (15A) - LH headlamp low beam, headlamp adjustment.
Power flows from the battery to the main fuse. Then it flows to the control coil and contact side of the headlight relay. When you turn on the headlights, the headlight switch provides ground to the control coil in the headlight relay and that operates the contacts. The contacts allow power to flow to the right and left hand headlight fuses. Power flows to the headlights. The headlight switch is what provides ground to the high and low beams on the headlights.
To diagnose, remove the headlight relay. Using a voltmeter, check for battery voltage on terminals 3 & 4 in the socket with the key in the RUN position. Then turn on the low beams. Test for good ground on terminal 1 in the socket. If you're not getting ground, then you've got a problem with either a bad headlight combo switch or a bad ground. If you get good ground on terminal 1, reinstall the relay, turn on the low beams and test for power in the headlight sockets. If you get battery voltage, that confirms you've got good fuses and wiring up to that point. Next, check for good low beam ground on the red/green wire in the bulb socket. If you're not getting good ground, it's either a bad combo switch or bad ground from the combo switch. Then turn on the high beams and check for good ground on the red/yellow wire in the bulb sockets.
It wouldn't hurt to clean the ID ground on the left side of the instrument panel, but based on everything you've said so far, this sounds like a bad combo switch
If fuses are good, I would suggest checking the relay that controls the High/Low beam settings of your headlights. It is located on the relay rack/center console, should be silver in color, with stamped (blue?) markings. If the relay is good, then the fault lies in the headlight switch. Check those two items in the order I suggested, and your issue should be solved.