Headlights went out while driving. Halogen lights

If the headlamps are out on dip and beam the most likely problem is either 40 amp main headlamp fuse blown or relay H-LP both in the fuse box under the hood, this is assuming your car does not have DRL's.

Hope this helps.

John (Britprius)

 

Just checked the wiring diagram for headlamps with DRL and the circuit is basically the same. What sort of level of electrics are you happy working with as I can pass on more information but do not wish to overload with information a beginner.

 

Ok check DRL fuse 7.5 amp. If ok, at one of the headlamps (does not matter which one) remove connector from bulb it will have 3 wires :- blue violet and brown, ground with a piece of wire the connector with the brown wire in it and try the lights in ready mode. Does the other headlamp work. If so check the DRL relay4 in the box under the hood near the center of the engine bay below the windscreen. If not check for 12v at pins 5 & 1 of the H-LP relay socket (relay removed) in the large fuse/relay box. Let me know how you get on.

John (Britprius).

 

Check at pin 6 (with the relay removed) of the H-LP relay socket with a volt meter for 12volts or a 12v bulb to ground if this is present the fuse is ok.

I think the next step is grounding the brown wire to one of the headlamps as in post 6 ( the one you tested with a replacement bulb will be the best to get at), as the ground return on the car with DRL is more complicated.

If you can read circuit diagrams there is one in the file library here on PC. The page you want is "Head lamps & fog lamps w DRL 2of2". Grounding this terminal misses out the whole of the DRL system grounding for the headlamps (runs the headlamps in the same way as the non DRL cars).

This will basically cut the faultfinding in half. The alternative to this is to ground pin 3 of the DRL relay socket (with the relay removed) does the same thing.

John (Britprius).

 

At leased you had a go at fixing it.

Hope the dealer does not rip you off. Please keep us informed with as much detail as you can as this may help others in the future. Good luck.

John (Britprius).

 

John,,,new member here. Saw some of your recommendations. Need help w/ an '05 Prius halogen headlight. Bulb is good but will not go back on after being shut off unless I wiggle the socket in the housing or the actual bulb socket is touched to ground momentarily. I checked the connections by just moving things around and there does not seem to be anything loose. I'm stumped. Thanks in advance....alex (Longinus876)

 

It is difficult for me to give precise instructions from a distance. Do you have a multimeter for testing? and the ability to use it.
The most common cause of this problem with the Prius is the ground wire terminal in the bulb connector being corroded or burnt. Changing the complete connector plug is the most reliable way to repair it.

John (Britprius)

 

Yes, have a meter and can check the resistance on all the connections. Will try that next. Could the ECM be involved? And would a code go to the ECM or elsewhere? Thanks again.

 

The ECM will not be involved. Fuses are also ruled out as the light can be made to work by moving the connector. If the fault appears on low, and high beam the only real suspect is the ground connection from the bulb to the body. Wiring diagram below.


John.

 

(Sorry for the necro and off-topic.)

@Britprius, did I understand your post correctly that either:

1. Grounding the brown wire in the headlight connector, OR
2. Grounding pin 3 of the DRL relay socket

will disable the DRL system? If so, could you please help me with more details/diagrams?

Also, are you referring to a US model with a DRL option added, or a Canadian model where DRL is required by law? (I have a Canadian 2004 Prius and I'm trying to use my fog lights as DRLs instead of the headlights to extend their life.)

Thank you!