Headlights out - checked fuse, bulbs - What now?

[tripleM]

My Dad's '01 Isuzu Rodeo's headlights only are out.
He checked fuse, bulbs.

What else can we check before we have to go for a professional mechanic diagnosis?

Thanks in advance for any insights!

 

[2oldtommy]

Could be a relay in the system? Check it out. --Oldtommy

 

[SuperEd73]

If it's only the headlights that are out and everything else like running lights and tailamps come on when you turn/flip the light switch, I'd say bad relay as well. Should be some form of relay box under hood somewhere near the battery.

Ed B.

 

[Jimmy9190]

Take a look at the Haynes Book for the truck, it will have the directionson how to remove the headlight switch and/or combination switch and check them with a volt-ohm meter. If the fuses and relays are all OK you may have a bad switch.

 

[Steve S]

Swithh ,relay bad connector etc. With a manual you can first find out where to check volts at the relay the fuse or circuit breaker .Then if the volts are good or bad go from there. That way basically you check the easy stuff first then if the voltages aren't there it is the switches or wiring or connectors .

 

[StevieC]

Here is the order I check it in...

Check for voltage with the lights turned on at the head lights, if not there, check at the fuse block, if not there check at the relay, if not there check at the switch, if not there check the power line that supplies the switch.

Some cars are equipped with a "Body" computer module that runs the lights through it so don't forget to check the connections there if equipped.

 

[SAATR]

Be sure to check the ground wire as well. High and low beam are two seperate circuits, and if both are out then a grounding issue if possible, especially if both the lights share a common ground wire.

 

[mechtech2]

Right. Body grounds to the sheet metal are often overlooked.
With any electrical problem, you can start at either end, or the middle.
It's up to you.
A relay is probably bad in this case, being that both lights are out, the bulbs good, and the fuses are OK.