I already got the switches. Figured they would have made a note on the website when ordering them. Any idea what I should search for or what Wilcox calls them??

- - -

Ahh, I found them!

 

Seeing this thread reminded me that I really should modify the headlight power circuit on my '72 and '73 so that the headlight switch just triggers two relays (one for each side) to supply power to the lamps...

 

Actually the 74 had 2 wires on the drivers side door jamb switch-one for the courtesy lights and 1 for the key buzzer-Both are grounds when the door is opened.

The alarm and the door ajar wires are on the switch at the back of the door. Both are ground leads.

 

Hi Roger,
Check you PM.

 

Forget about my post (38) and trust Roger.

 

Thanks Pete

(I have seen 3 wires in the past but they were for an aftermarket alarm.)

 

The dimming feature of the switch is a simple rehostat. The more you dim your dash lights the hotter the switch will get as the current is removed from the switch in the form of heat.

I always keep my dimmer on high as it gets hot if I dim the lights. 1840's technology at work here invented by Charles Wheatstone of the Wheatstone Bridge fame, first year electronics you learn this.

 

Grease or Zerk fittings were patented by ole Oscar Zerk back in 1929,learned that in first year auto mechanics.
Me and Oscar used to run the bars and pickup babes back in the good old days.

 

Here's some info from my experience with the switch in my 71 that I just went through when my courtesy light would not come on. The light switch had a brown stain (presumed burnt) mark on the plastic next to the white wire terminal. I tried to seat the harness fully into the switch. could not get it fully seated since the mounting lug for the male connector prevented it. When I checked the the white wire and black wire under the dash to the courtesy light I found that the white and black had welded together behind the kick panel. I separated and insulated them and "whoa" the light came on This is my story and I'm sticking to it.
MIKE

 

Ah yes grade 9 auto mechanics, best 3 years of my life

 

I've studied and studied the schematic.. pulled a switch apart and looked at pictures until I'm blue in the face....

I have the original switch in my possession and took it apart piece by piece.

So... lets start with the switch. The internals of the switch are in perfect working order. There are no sign's of an over-load inside the switch. All contacts look clean, all connector terminals are also clean and actually look new.

On the rheostat: The rheostat is fried which comes as no surprise to anyone based on the pictures posted. The wire is cooked in two places.

The only wires affected by the rheostat:

Dark Green runs to the fuse block and then to the gray wires that light up your dash.

Brown which supplies power to the rheostat though a jumper terminal on the switch. The brown wire supplies power the tail lamps and to the marker lamps when the switch is pulled in either the first click (parking lamps) or the second click (headlamps).

Orange: Orange wire powers up the clock, the parking lamps, tail lamps, courtesy lamps, rear storage lamp, and cigarette lighter. The orange wire is also the power feed for the brown and green wire. I’d lean in this direction except for the fact that all of the switch terminals show no sign of over-heating… A dead short on orange as most know will cause issues almost anywhere.

White.. The white wire supplies ground to the courtesy lamps... This wire only plays a part in they system when you rotate the switch know to the left fully. This push's the grounding tab into the actual bracket that holds the headlamp switch together and supplies ground.

Hot to ground… Meaning a short somewhere to the grounding system… an example would be a hot wire touching the speedo can. This would make the grounding bracket hot instantly..

In looking at the original switch, I see a "tit" on the flat finger that rides on the rheostat... I'm intrigued by this because the tit is on the edge of the finger and not on the rubbing surface... As if it is a trace of a wire that hit it... It looks almost like a weld mark... But then this thing did get hot.. and it is possible something hit it after the fact. Maybe a screw or clip fell on it?

This entire thread is almost like the "chicken or the egg".. It's almost impossible to tell what went wrong in the car without having a car to dissect. What I will say is that whatever hit this hit it hard! The rotating barrel is completely melted.

I don't think a short on the white wire (positive on the ground) could have caused this, based simply on the fact that the wire alone would fry before the switch got this hot.

I'm afraid that I've not read all the post since my last visit either. I see where the rear compartment wires (orange/black) have been cut… and as sad as it may seem.. nothing points me in one direction or the other without out having a car to probe.

Willcox