99' volvo vnl64t wiring problems?

Do the signals on the drivers side work? If so it's not the flasher. If the light is coming on but not flashing that is usually simply a burned out bulb, probably passenger side rear. What is that particular light doing? Does it come on but not blink or is it out when you turn on your right turn signal? These circuits are designed so if you have a bulb go out, such as the rear passenger side, the front passenger side will come on but not blink. This and the dashboard indicator coming on but not blinking are your indication that you have a bulb out. Check that first and let me know what you find.

 

I agree with the bulb being burned out, but wouldn't you have caught this during a pre-trip?. Regarding the radio, has it worked in the past? I ran a Volvo for a few months and the radio didn't work but I later discovered there was a button on it (don't remember which one) that kept it turned off, even when pressed. I know, that all doesn't make sense.

 

This is happening to mine as well.

1999 Volvo VNL64T.

My driver side headlight is out. I changed bulb, no good. Swapped out bulbs, left to right to compare. Bulbs are good.

Checked fuses. Swapped out fuses as well. Passenger side still good.

Checked relays, behind the cup holder. Swapped them out as well and still driver side out.

I will check grounding and do more research when I get a chance during New Years and post my findings.

 

PTR - On the flashing circuit, you'll want to check the lamp and socket to make sure there's good contact. Maybe now would be a good time to stick in a new bulb and see if that changes anything (or swap it with the side that works).

If the lamp contacts and socket is clean, I would turn park lights and 4way on and test the contacts (is this a dual filament, 3 contact lamp and socket?) with a multi meter to check for 12V and switched (flashing) 12V. Also check to make sure it's the right bulb, and check the filament(s) for resistance with the ohmmeter - I've seen lamps that shorted out of sight in the base before. It sounds like a dual filament lamp with the "high" (flash) side burnt or shorted.

Blanco - On the headlight I'd start with a multi-meter at the headlamp plug. Check one contact in the plug to the next with the headlights turned on. (As long as you have the meter switched to Volts DC you can't hurt the meter or the truck.)

If you don't get voltage at the headlamp plug, there should be a harness plug not too far away to test it again - just pull the harness apart far enough to get the leads in. It sounds to me like you have a break in the harness or a very bad connection. I'd also take a very close look at the lamp in as close to total darkness as you can - is there even a faint bit of light showing? If there's any light at all, you have a bad connection - not a dead short.

You also might want to check from the negative contact in the headlamp plug to the actual frame of the truck, and from the 12V contacts in the plug to the frame. Sometimes if ground is screwed up a meter won't show voltage at all.

Electricity can be the easiest thing in the world to troubleshoot, or the biggest invisible pain in the ##### ever. It needs clean contacts to travel, and wires can (and do) break or corrode in the middle sometimes. Good luck and I hope it works out!