Community Forums

barmcd · 01-17-2022, 01:43 PM

I think my headlight switch is bad. I went out the other night to dump the air from the suspension and couldn’t see the labels on the air dump switch. I pulled the headlight switch on to illuminate the label and the headlights came on, but not the interior lights. I fiddled with the knob and the interior lights go on and off as you rotate the knob. It’s an on/off type action, not like a rheostat.

I went out and looked at the lights and they all work except the driver’s side marker and parking light. Both blink when the turn signal is engaged.

I checked my schematic and the voltage for the marker and parking light come straight from the switch.

My main question is this. Does the jack on the back of the headlight switch just pull straight off the back of the switch? It’s hard to tell from looking at it.

wamcneil · 01-17-2022, 01:57 PM

Oh wow. It's been a while since I did that.
I think the plug does just pull off the back. The tricky part is the knob. There's a button you have to depress in the switch to remove the knob and shaft from the switch housing.

https://www.youtube.com/watch?v=DH1WlwLN12Y

As I recall, I took off the shaft and pulled it off the dash, then pulled off the plug.
Cheers,
Walter

PeteandDeb · 01-17-2022, 05:42 PM

same problem but newer Monaco. Anything special about the headlight switch on an '08 Diplomat? I can sometimes turn the shaft back and forth and find one spot where the dash lights come to life ... but don't want to chance another ride in the dark trying to drive and keep a flashlight focused on the dash.

jacwjames · 01-17-2022, 06:15 PM

I just replaced mine last month. Hard to get to, I ended up taking all the screws out of the dash and tipping it forward. If you have access to it the job will be much easier.

There is a button on the bottom of the switch that you press and pull out the knob.
On my headlight switch the wiring harness pulls off the switch on the top. It was hard to get off, had to use a small screw driver to help pry it off.

On my switch the rheostat portion was burnt off so none of the dash and switch lights worked.

barmcd · 01-17-2022, 07:18 PM

My dash is so brittle I’d be afraid to take the screws out! I’m hoping I can replace it without doing that.

barmcd · 01-17-2022, 07:19 PM

Quote:

Originally Posted by wamcneil

Oh wow. It's been a while since I did that.
I think the plug does just pull off the back. The tricky part is the knob. There's a button you have to depress in the switch to remove the knob and shaft from the switch housing.

https://www.youtube.com/watch?v=DH1WlwLN12Y

As I recall, I took off the shaft and pulled it off the dash, then pulled off the plug.
Cheers,
Walter

Thanks for that video

jacwjames · 01-17-2022, 07:55 PM

Quote:

Originally Posted by barmcd

My dash is so brittle I’d be afraid to take the screws out! I’m hoping I can replace it without doing that.

I have a heat vent above the light switch. I did remove it and initially tried to to get the light switch out using that as access. It helped but I couldn't pull the wiring harness off. Finally decided to just pull the dash.

My dash is cracked up also, not much I can do about it now but try to be careful.

barmcd · 01-18-2022, 08:58 AM

I removed the switch this morning. Luckily I had plenty of room from the top opening in the dash. I had to put a popsicle stick on the button to depress it to remove the knob stem.

I had enough slack to pull the switch up above the dash to measure 12 VDC on pin 4 and 7 of the switch so it definitely has to be an issue inside the switch.

As far as I could tell, There was no number on the switch, just “Made in Mexico”.

Skip426 · 01-18-2022, 09:15 AM

1972 GMC 1/2 ton headlight switch . Approx $8

jacwjames · 01-18-2022, 09:39 AM

https://www.amazon.com/dp/B000C9SAJC...roduct_details

D1588 GM switch, I decided to buy from AMASON since it was delivered and easy returns. Could get after market much cheaper.

barmcd · 01-18-2022, 12:20 PM

The switch fixed the interior lights, the bulb was blown on the parking lights. I picked the switch up at NAPA for $15. It was for a ‘73 Chevy pickup.

PeteandDeb · 01-19-2022, 11:01 AM

With the top cover removed, it was fairly easy to get my switch out. Pulling the shaft out was the only moderately difficult feat.
As Jim noted, the D1588 switch is what was installed in my Diplomat. In checking it out for an actual ACDelco part rather than Chinese crap, the best price and delivery by about a buck was Rock Auto. Amazon used to be the goto but their prime delivery out here has gone from "two days" to "between one and two weeks" for in stock items.