Dome/map lights not working.

[6cuda6]

Anyone ever come across the dome/map lights not working?
I have power to them but i suspect i have a bad ground, possibly at the headlight switch as the lights dont come on in "dome" mode and its one of the
grounds. What is stumping me is it looks like the other ground for the second switch position on the dome lights is at the clearence lights but they
all work....anyone have this issue before?

Cheers
--
Rich Mondor,

Brockville, ON

77 Hughes 2600

 

[jim kanomata1]

Depend on year, thevhead light switch need to rotate to activate

On Sun, Jul 28, 2019 at 7:12 PM tonka6cuda6--- via Gmclist <

> Anyone ever come across the dome/map lights not working?
> I have power to them but i suspect i have a bad ground, possibly at the
> headlight switch as the lights dont come on in "dome" mode and its one of
> the
> grounds. What is stumping me is it looks like the other ground for the
> second switch position on the dome lights is at the clearence lights but
> they
> all work....anyone have this issue before?
>
> Cheers
> --
> Rich Mondor,
>
> Brockville, ON
>
> 77 Hughes 2600
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502

 

[Ken B]

I assume that you understand the operation of the rocker next to the dome lights. It not, here it is. The rocker switch has 3 positions
1. In the center position the dome light is off.
2. In the lower position the lights are controlled by the rotation the headlight switch. On is all the way counter clockwise.
3. In the upper position the light should be on.

Note: I may have 2 and 3 above reversed. (Upper position vs. lower)
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[Ken B]

Well I should have read you posting more closely before responding. You already understood how they were suppose to work....Sorry

It has been years since I have been up there and I do not remember where the ground is attached for the mode where the rocker switch turns them on. Do
not rely on the clearance lights for a good ground. Many of then are reversed and the ground at the bulb is really hot (+12 v). It does not hurt
anything there because they are mounted on non-conductive fiber glass.

In the other mode where where rotating the dome/ headlight switch to turn them on, the ground comes from the mounting of the headlight switch to the
aluminum plate on the instrument panel. In my case when it failed it was an oxidized connection between the headlight switch and the aluminum plate.
I simply grabbed the switch and rotated it about 1/8 of a turn each way and that cleaned up the electrical connection. I never even loosened the
switch when I did it. That was about 15 years ago and they still work.

--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[6cuda6]

Its a 77 Jim.

Thanks Ken ill give that a shot.
--
Rich Mondor,

Brockville, ON

77 Hughes 2600

 

[6cuda6]

So i got them working in dome position....bad ground for one and dirty contacts in the switch for the other.

Still dont work with the "dome" position of the headlight switch and im just going to replace the headlight switch....this one is getting gritty
anyways.
--
Rich Mondor,

Brockville, ON

77 Hughes 2600

 

[6cuda6]

Well another adventure with this one.....went to change the switch and someone put the nut on so tight i cant get it off....now i need to get the
headlight switch nut too.....on the upside the dome lights now work properly though.....lol.
--
Rich Mondor,

Brockville, ON

77 Hughes 2600

 

[Deb]

I am following your adventures with this with interest, Rich. I have no dome lights or cluster lighting (the wee 4A fuse is good). So I suspect the
headlight switch (first - but being electrical, it could be so many other things, I know! ). Haven't tried to replace it yet, but maybe before I do
I will make sure I get an extra nut (to keep the one behind the wheel company). Headlights work. Did you replace the switch and that corrected your
problem, but now need a nut to hold it in place? Or did things magically return to function during your "laying-on of hands"?

I haven't gone through all of the switch positions, in all of the situations (engine running, not running, shore power on, etc) so I can't be certain
if I have NO dome lights, or I just didn't test them in the correct combination. I have never needed them (or the cluster lighting) since I don't
drive at night. But given that one cannot always determine when one will be required to drive, I suppose that is the next project I can attack in my
down time.
--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!

 

[emerystora]

Deb
The dome lights don’t work through any of the push pull positions of the headlight.

When you rotate the headlight you can dim your dash lights. It you turn it all the way there will be a click and a switch will turn on the dome lights. (If the switch at the dome light is not in the off position )

Emery

>
> given

 

[6cuda6]

Ded, Emery is correct, you need to turn your headlight switch counter clockwise with the dome light switch in the upper position.....they should come
on.

Mine at first would not come on at all....i discovered that i had 2 problems....the first was the actual dome light switches so i took them apart,
cleaned and reinstalled....the lights then worked in the down or manual position but not in "dome" with the headlight switch.

The second problem was the ground at the headlight switch itself. Ken had mentioned trying rotating the switch body a little to get better contact
with the dash frame, which is the ground but sadly it didnt get resolved so i elected to change the switch....appon trying to change the switch
someone put the nut on so tight i couldnt remove it but it did move things a bit and i guess the switch found a clean ground point and the dome lights
now work.

I am still going to replace it but need a new switch mounting nut before i try again.
--
Rich Mondor,

Brockville, ON

77 Hughes 2600

 

[Deb]

Thanks Rich & Emery. I know of the counter-clockwise turning of the headlight switch - I owned a couple of old cars in my youth (my '67 Mustang was
my favourite) and I did try turning the switch (several times) both for the cluster lights (nope) and counterclockwise past the 'click' to get the
dome lights (no joy there either). But I will look at the dome light switches, as well as try to 'jiggle' that headlight switch to see if that helps.
I still think replacing the switch won't hurt in the overall scheme of things tho'. Nice to know about the ground point on the headlight switch.
Might be that could be part of my problem.
--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!

 

[Ken H.]

I'm surprised that during all this headlight switch discussion no one has
mentioned how to remove the knob. I'm sure there are those among the
"audience" who'd be completely baffled by that old trick. So, for their
benefit, just in case: The headlight switch knob is permanently attached
to a shaft which extends into the switch. To remove that shaft, one must
depress a spring-loaded button on the side of the swich (beneath the
dash). That "side" should be the bottom, but can be to the top, bottom, or
either side, dependent on how the last tinkerer left it. After you find
the button, pull the knob to the "headlights" position, depress the
buttton, and keep pulling -- the knob and shaft should come free.

With the knob removed, the screwdriver slot for the mounting nut will be
exposed. To re-install the knob, just align the shaft's flatted side with
that in the switch, and push it into place. The spring loaded button
should latch the shaft and restore the switch operation.

Takes a LOT longer to tell that than to do it!

Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, Troy-Bilt APU, etc., etc., etc.
www.gmcwipersetc.com

On Sun, Aug 18, 2019 at 3:14 PM Deb McWade via Gmclist <

> Thanks Rich & Emery. I know of the counter-clockwise turning of the
> headlight switch - I owned a couple of old cars in my youth (my '67 Mustang
> was
> my favourite) and I did try turning the switch (several times) both for
> the cluster lights (nope) and counterclockwise past the 'click' to get the
> dome lights (no joy there either). But I will look at the dome light
> switches, as well as try to 'jiggle' that headlight switch to see if that
> helps.
> I still think replacing the switch won't hurt in the overall scheme of
> things tho'. Nice to know about the ground point on the headlight switch.
> Might be that could be part of my problem.
> --
> Deb McWade
> Logan Lake, BC, CAN
> "Li'l Sister"
> '77 Kingsley, 403, EBL EFI;
> TZE167V101404
> It's Bigger on the Inside!
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[Deb]

Thanks Ken. I had read the process (somewhere) on this forum, but you have described it very clearly. I now have a very good idea of what I should
be looking for. Someone (can't remember who) posted pics in the photo site, comparing the OEM with his replacement (best fit) and I believe there was
something about it in the GMCMI help files, which was where I found the link to the photos. Now to see if I bookmarked those pages!
--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!

 

[6cuda6]

> Thanks Ken. I had read the process (somewhere) on this forum, but you have described it very clearly. I now have a very good idea of what I
> should be looking for. Someone (can't remember who) posted pics in the photo site, comparing the OEM with his replacement (best fit) and I believe
> there was something about it in the GMCMI help files, which was where I found the link to the photos. Now to see if I bookmarked those pages!
>
> I did - It was arch in 2007. A link to the first of a series of pics in the midst of his dash update
> http://www.gmcmhphotos.com/photos/dash-repair/p16285.html in case anyone else would like a visual.
> And also jharper http://www.gmcmhphotos.com/photos/headlight-switch-removal-2freplacement/p21565-the-headlight-switch-the-challenge-begins.html
>
> I started text messaging links to myself as I found things of note (especially those I found by accident) - found it easier than just bookmarking,
> especially since I often found them while on my phone. These, fortunately, were 2 of them.

Deb dont hesitate to ask about what i did and how i did to clean up the dome light switches if you need assistance.
--
Rich Mondor,

Brockville, ON

77 Hughes 2600

 

[Deb]

Thanks Rich. You may well be hearing from me. Today is lunch with a friend and getting the scoot running (properly!). Tomorrow - I may attack the
lights in the coach.
--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!