Second post....Please be gentle....Yes, I know this is the Accord forum and I have a Prelude question...but wait....they use the same headlight parts. Here goes:

Looks like a great resource site.

I have a '96 Prelude. Problem started about 10 days ago....

I cannot dim the headlights. High beam and low beam stay on no matter what (well actually, on day 3 everything seemed to work OK...then it did it again).

I thought it was the switch on the steering column...$86 and a new switch later I was convinced that was NOT the problem.

I thought it was the dimmer relay under the hood....$19.95 and a new relay later I was convinced that was NOT the problem.

I thought it might be a bad ground at G201....just finished checking/cleaning that sucker and have perfect continuity to ground at the battery.

I unplugged all 4 headlights and plugged them in, one at a time, thinking something might be funky with one of them. Each one burned brightly no matter how many times you clicked the ding-danged dimmer switch.

I'm certain that someone here will point out the obvious solution leaving me saying "Well, DUH!!" but at this point I've lost all pride and willingly beg for assistance.

Can anyone point me in the right direction?

Thanks!!

 

Pull your "Dimmer" relay. Turn your headlights on and see if only the "low" beam lights are on. Leave the lights on and plug the "Dimmer" relay back in. If the "high" beam lights come on without you moving the dimmer switch then it sound like you have a "ground" on the wire between the dimmer switch and the dimmer relay. Best way to check it would be to get one of those "12 volt" test lights used for checking electrical circuits (looks like a screw driver with a light bulb in the handle and had a clip lead coming off the end). Clip the lead to the battery + terminal and then use the pointy end to check the wiring between the dimmer relay and dimmer switch. If the wire has a ground (should not until you operate the dimmer switch) then the light will come on. Find the ground and you have fixed the problem. Find someone with a wiring diagram for your Prelude before you start. A picture really is worth a 1000 words.

 

Pulled the dimmer relay from the under hood fuse/relay box and turned on the headlight switch....

High beam and Low beam (all 4 lights) come on.

 

On the "High" beam connectors at the head lights one of the wires at each connector is Red with a blue trace line. This Red/blue wire is a common point for both high beam headlights and goes to the dimmer relay contact. If you are getting the high beam lights on with the relay pulled then you have a "Ground" on this Red/blue wire somewhere between the dimmer socket in the fuse box and the head light connectors (right or left side). Look for wires that don't belong that have been attached to the high beam connectors or wires that are rubbing against the body and have a bare spot touching the frame of the car.

 

Thank you, ex-r-wagon, I'm thankful to have someplace to start looking. I'll check this tonight when I get off work and report back.