Headlight head-scratcher...

[dsmelfi]

I've been having some headlight flickering issues, so I've been chasing down grounds, cleaning up power etc... got the WH harness upgrade with the 8700 Evolution LED. Here's the weird thing... I'm driving home, paying close attention to them, and everytime I touch the clutch they dim.. I don't fully engage the clutch so no change in RPM, just have to barely touch the friction point and they dim. Even stranger, it happens when I'm parked and the ignition is off, it is more noticeable when the key is in the on position, engine still off, but they flicker when the key is off and I press the cutch as well.

I have a blueprint 306, AX15, ProFlo4 EFI and Centech harness all less than 8000 miles. There was some wiring close to the clutch linkage, I believe the EFI exhaust sensor and the reverse light cable, but neither were actually toughing the linkage... Also, nothing under the dash I can see with any wires touching or in the way of the clutch travel.

I'm still chasing down all the grounds I can find, but any ideas would be appreciated.

Thanks.

 

[gnsteam]

Do you still have the floor mounted foot dimmer switch? If so check it out. Many year ago I had a headlight flickering issue. Until one very dark night out in the boonies, when the head light quit. Had to drive home with and old flashlight. The issue was a shorted out dimmer switch.

 

[dsmelfi]

Thx gnsteam... I do have the dimmer switch and it does work.. I have the same flicker / clutch sim with the brights on or off. I'll definitely check that out!

 

[Lawndart]

I'd say it is your headlight switch. When I bought mine and drove it back from PA, the lights would cut out - high or low beam.
Installed a relay harness and never had the problem again - high or low beam.
This harness is sold by most of the vendors - plug-n-play.

 

[dsmelfi]

Thanks Lawndart. I have the aftermarket harness installed but I'll check the switch as well.

 

[Broncobowsher]

Bad (weak) engine to body ground. When you load up the clutch pedal you get a better ground through the clutch linkage.

 

[66CTBronco]

i was going to say the same as bowsher, but if ground were a high resistance connection, and touching the pedal improved the ground, the lights would get brighter when you touched the clutch pedal. I think the though process is sound though, it appears a change in connection resistance is being made when the throwout arm touches the throwout bearing and the pressure plate fingers. Not quite sure how yet i'm still working on that lol. A quick check is with the help of an assistant (to touch the clutch pedal) make two voltage measurements: hot lead from behind a headlight to the negative terminal on the battery, and return lead from behind a headlight to the negative terminal on the battery. One of them is going to change - either the battery side will go lower (from 14 or so to 12), or the ground side will go higher (should be close to 0, may climb to 1 or 2). That would be my place to start.
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[Broncobowsher]

The reference point of the voltage regulator ground can change things.

 

[dsmelfi]

Quick update and thank you all for the help. Turns out the main ground from the block to the frame was terrible.. PO used a 1/4 inch bolt through a 3/4 inch hole with some large washers and it was loose.. I could spin the bolt by hand. Also, the Alternator had a bad ground.. drilled a new frame ground and cleaned up the alternator to engine block bolts and the lights are solid. Appreciate the help!