Help My headlights on 4104 have a problem

[dellisor]

I have a 1960 PD4104 and I am in Oconee state park in south carolina and I have a problem with my headlights. They wont shut off ( unless I pull the battery cable ) I took the headlight switch out and checked the wire voltage with switch on and off. The voltage was 12.7 with switch on and .27 volts when off. the headlights are slightlly dimmer when switch is off but no where near off. Its all the original wireing so any help would be appreciated . My E-mail is nuke884@yahoo.com Thanks Dave Ellisor

[zubzub]

Probably a frayed wire somewhere.  As the switch isn't controlling it look in the driver's panel.  you can find the wires going to the HL there and disconnect them for now to turn the HL off.  Most likely the cross wiring is in the dash panel or the junction panel.  When I looked at mine the wires were very old and heat decayed/corroded. If you are running the original wiring, I would suggest replacing the wires from the H lights to the panel, and installing a temporary switch for now.  You can get at the HL from under the dash area (LSide) and through the access panel by the hinge mechanism (RS).  The manual has a decent wiring diagram, in this case the panel illustrations with the number breadown will give you the info you need.  Deal with this properly, the PO of my bus didn't and I experienced full HL loss at highway speeds at night.

[dellisor]

It seems to have fixxed its self, last night they where still on but today they are off so if a relay had hung up maybe it fixxed its self. I would like to know where the relay is incase it does it again. Today I need to ajust the shifter linkage for first and second gear as it is poping out of first and getting hung up in second.I think all i have to do is screww the linkage about a quarter inch toward the motor but onc e i do this i think it will fix the problem. Thanks again Dave   

[Len Silva]

To the best of my knowledge, there are no relays in the lighting circuits on a 4104, at least not up to 1957.

The circuit is pretty basic.

From the main buss in the driver's panel to CB 11 to term 21 to headlight switch to term 82.

From 82, it goes to the headlight/Foglight selector switch, then to the dimmer switch, then to the headlights.

That's all there is.  Check those places and the headlight grounds and you should be in business.

Of course, there's no telling what other people might have done since.

You can find the wiring diagram here: http://manuals.lenstudio.com/GM_PD4104MaintX-5818.pdf