flickering headlights 1978 31 FC

[Strayhound]

I recently replaced the headlight dash switch after all four lights failed while driving. The switch was slightly burned and the headlight terminal was loose.

I was hoping that was the problem. But after reinstalling the switch and replacing all the bulbs, I continue to have a problem.

All four lights begin to flicker about 10 seconds after they are turned on with the 3208 Cat running and the bus parked.

They don't flicker, however, when the motor isn't running.

Nor do they flicker when I just run the low beams with the motor running.
They only flicker when I activate the high beams.

The low beams are Hella H4; The high beams are Hella H1.

I have checked the grounds on both all four lights and they appear to be good.

One RV mechanic suggested installing a 30 amp breaker and a relay between the battery and the high beams to reduce the draw off the dash circuit.

Any other suggestions?

Thanks
John

Thanks!

[rwoody]

ck the voltage--it jumps a lot and it is switch related

i had that problem on freebird and did the relay mod that john F sells and it fixed it..i believe i did it at rats with pete helping and lots of folks watching!

[Jim Harvie]

I'd be checking the voltage at the dimmer switch.... both sides

[Bill Pape]

Strayhound,

John must be napping , he is on "Finn Standard Time". He may answer, when we are all sleeping.
But here is John's website, continue to click on next in the upper right corner for more information.

http://www.pbase.com/iamflagman/image/32546768

There is more information on this Forum, find by doing a search.
Get the load off of the ignition switch and the headlight switch.

[MRPutz]

Hey John,

The only other connection that is NOT common to both high and low beams is the foot switch. Either loose connection or corrosion inside. But another theory could be your Alternator/regulator? Are you still running that old remote regulator mounted by the battery compartment? Could be the extra draw on the system causes the regulator to fluxuate?

[Strayhound]

Thanks everyone for the advice. I'll try the double relay option. Is this issue related to using halogen bulbs instead of incandescent? The 1978 wiring diagram shows all four headlights and the rear running lights on the same circuit. Will this option impact the rear running lights in any way?

[Rick]

If you wish to apply the same modification to the tail lights John Finn has a write up on that also.

[Strayhound]

I put in the relays and the problem appears to be solved! Thanks again!