Strange problem with headlights

[cinan]

I found out today that my passenger side headlight low beam is not working.  High beam is ok but not low beam.  I instantly thought fuse or bulb.  The fuse inspected ok and I tried another bulb that I have both didn't fix the problem.  On closer examination I am getting 12v through the low beam wire and the connector onto the bulb when it is not connected to the bulb but when the circuit is connected with the plug to the bulb there is no voltage.  What could be causing this problem is it possible there is a relay that may have blown ?  it seems that under load the voltage isn't there ?  very confused.

Andrew

[Carzee]

This is a 110?

If one headlight low is ok then the headlight relay would be ok I guess. I'd expect one relay for hi beam and one for low beam. Although my Yaris had separate relays for left side headlight and another for the right side. Why, who knows.

Just guessing, whats going on regards the earth? Do the hi beam and low bean earth in the same wire/place?

[cinan]

Yep a 110 Snr Commander.  There are three wires going to the headlight bulb as per any standard halogen light.  Red/blue for low beam +ve, red/white for high beam +ve and a black for ground shared by both L/H.

I had the same thought re the relay if the drivers side is ok then in theory any low beam relay should be ok.  I was surprised to see a fuse for each side though.

[Young Eric]

try cleaning the fuse holder, mine were slightly corroded and after a good clean up all was well.

[FFRMAN]

try cleaning the fuse holder, mine were slightly corroded and after a good clean up all was well.

Yes I had the same problem with the indicator relay, it kept failing until I cleaned the fuse connections

[Snail]

Did you ever get to the bottom of the issue? I have exactly the same problem, spent hours with the multimeter trying to work it out.

[muddy]

Try a test lamp (puts load on circuit ) say a 5 watt lamp and see the results -----multi meters have problems with high resistance connections .

They will read 12v on no load ,but when a load is added say a lamp with a high resistance in circuit  you will find the lamp wont work and no voltage at bulb.

 Take your multi meter (circuit in operation mode) and see how far along the circuit 12v is present as soon as voltage is lost ,there is an open circuit or high resistance ,there is a good chance you will find a high resistance accross the fuse 

[cinan]

My issue was caused by dodgy bullet connectors behind the headlights.  Once they were pushed back together properly everything works.  When I get around to it I will remove the connectors and solder the connectors together.

[BadCo.]

My issue was caused by dodgy bullet connectors behind the headlights.  Once they were pushed back together properly everything works.  When I get around to it I will remove the connectors and solder the connectors together.

There are so many of these in the Perenties. I had one short out on the difflock actuator in the dash.