Electrical short -- no panel lights - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**ThreeQuarter** · 09-07-2002, 08:45 PM

Trying to chase down a short in a '68. It's in the instrument cluster lights circuit (lower RH fuse). I unplugged the cluster and it still blows a fuse. Any (other) places in this circuit that are notorious for shorting out? I will be studying wiring diagrams for awhile tonight.

Thanks in advance. Ben

*Zkast* · 09-07-2002, 09:25 PM

If im not mistaken, the parking light fuse feeds the cluster AND the parking lights. Check near the rear for hacked installs of trailor wiring.

**ThreeQuarter** · 09-07-2002, 09:45 PM

Nope, parking lights still work.

**ThreeQuarter** · 09-07-2002, 10:49 PM

Well, I got the panel lights working. Don't know what I did but I took it all out and put it all back in and it works OK now.

Now to fix the other problem: the LH headlight and blinker circuits are crossed, so the blinker comes on with the bright lights and the bright headlight blinks when I signal. They work fine when I unplug the cluster so I guess they're crossed on the circuit board. Time to order a new one...

*Zkast* · 09-07-2002, 10:52 PM

lol whoa what a mess

Check the wiring to the connector, make sure no one has butchered it and crossed the High beam indicator light with the LH signal indicator light.

O'l Buck · 09-08-2002, 12:06 AM

i'm guessing you have a big bad ground problem somewhere, that is usually the cause of the blinkers comming on, or just one blinker with the headlights, or taillights, at least in my experience. I had alot of these problems running classic semi-trucks for 5 years.....big power, pretty trucks, more wiring problems than Carter's got pills!!

Hutch · 09-08-2002, 02:17 AM

Did this just start happening?
If so do as O'l Buck said and check your ground wires closely.
If it has always (or since you have acquired it) been that way
check the color code on the connector on the plug to the printed circuit to the dash this link will help
Tech Tips

You also may want to look closely at the printed circuit on the back of the dash these are repaired rather easily.

I have also seen weird things happen when the emergency flasher is partially depressed on the column switch.

I hope this helps

**ThreeQuarter** · 09-08-2002, 03:42 PM

Unfortunately this isn't my truck, I've done work on it ever since my 82 year old friend found out I know these trucks pretty well. He bought it new in '68, and it's a pretty nice mint green C10. (I'll have to get pics sometime.) So I don't know when all these problems started, and I'm usually patching up stuff that the previous hack mechanic did. (hehe I feel sorry for the guy who has to follow me!

)

I'm expecting to get a new circuit board for it, and think I should also get a light switch. That should fix all the lighing problems, but now the blower motor isn't working. I'll post a new thread for that one...

I think what we have here is a bonafide gremlin!

**ThreeQuarter** · 09-16-2002, 07:40 PM

Did some work on it this weekend. The headlight/blinker problem was due to a pair of crossed/twisted tabs where the wiring harness plugs into the cluster. One was hanging by a thread and came off while I was repositioning it. New printed circuit board from Kenny's: $50. Maybe that will fix the short in the cluster lights, too.

The A/C problem is either the fuse box or the relay. He needs a new fuse box anyway so I'm already replacing it (got one for sale?), and I ordered a new relay from Kenny's just in case; $15.

09-07-2002, 08:45 PM	#1
ThreeQuarter Senior Member Join Date: Jun 2000 Location: Texan in Iowa Posts: 2,523	Electrical short -- no panel lights Trying to chase down a short in a '68. It's in the instrument cluster lights circuit (lower RH fuse). I unplugged the cluster and it still blows a fuse. Any (other) places in this circuit that are notorious for shorting out? I will be studying wiring diagrams for awhile tonight. Thanks in advance. Ben __________________ Ben '68 Chevy C10 Custom LWB 327/TH400 2nd owner '16 GMC Sierra 1500 SLE Dblcab 4wd 5.3

09-07-2002, 09:45 PM	#3
ThreeQuarter Senior Member Join Date: Jun 2000 Location: Texan in Iowa Posts: 2,523	Nope, parking lights still work. __________________ Ben '68 Chevy C10 Custom LWB 327/TH400 2nd owner '16 GMC Sierra 1500 SLE Dblcab 4wd 5.3

09-07-2002, 10:49 PM	#4
ThreeQuarter Senior Member Join Date: Jun 2000 Location: Texan in Iowa Posts: 2,523	Well, I got the panel lights working. Don't know what I did but I took it all out and put it all back in and it works OK now. Now to fix the other problem: the LH headlight and blinker circuits are crossed, so the blinker comes on with the bright lights and the bright headlight blinks when I signal. They work fine when I unplug the cluster so I guess they're crossed on the circuit board. Time to order a new one... __________________ Ben '68 Chevy C10 Custom LWB 327/TH400 2nd owner '16 GMC Sierra 1500 SLE Dblcab 4wd 5.3

09-08-2002, 12:06 AM	#6
O'l Buck Recovering Truck Driver Join Date: Mar 2002 Location: Orleans, NE USA Posts: 1,883	i'm guessing you have a big bad ground problem somewhere, that is usually the cause of the blinkers comming on, or just one blinker with the headlights, or taillights, at least in my experience. I had alot of these problems running classic semi-trucks for 5 years.....big power, pretty trucks, more wiring problems than Carter's got pills!! __________________ 67 K-20 350, SM465, Eaton rear, 4.56 no spin option 00 Dodge 2500 4x4, 24V cummins, 5 speed Chad South Central Nebraska

09-08-2002, 02:17 AM	#7
Hutch Registered User Join Date: Oct 2001 Location: Grapevine, Tx. Posts: 2,142	Did this just start happening? If so do as O'l Buck said and check your ground wires closely. If it has always (or since you have acquired it) been that way check the color code on the connector on the plug to the printed circuit to the dash this link will help Tech Tips You also may want to look closely at the printed circuit on the back of the dash these are repaired rather easily. I have also seen weird things happen when the emergency flasher is partially depressed on the column switch. I hope this helps __________________ John Hutchison Grapevine,Texas 68 1/2 t swb 68 Mustang 69 Jaguar 71 1/2 t swb 88 Supra CompTs6m 93 Escort GT 2005 Corolla XRS

09-07-2002, 09:25 PM	#2
Zkast Account Suspended Join Date: May 2002 Location: Olathe, Kansas Posts: 929	If im not mistaken, the parking light fuse feeds the cluster AND the parking lights. Check near the rear for hacked installs of trailor wiring.

09-07-2002, 10:52 PM	#5
Zkast Account Suspended Join Date: May 2002 Location: Olathe, Kansas Posts: 929	lol whoa what a mess Check the wiring to the connector, make sure no one has butchered it and crossed the High beam indicator light with the LH signal indicator light.

09-08-2002, 03:42 PM	#8
ThreeQuarter Senior Member Join Date: Jun 2000 Location: Texan in Iowa Posts: 2,523	Unfortunately this isn't my truck, I've done work on it ever since my 82 year old friend found out I know these trucks pretty well. He bought it new in '68, and it's a pretty nice mint green C10. (I'll have to get pics sometime.) So I don't know when all these problems started, and I'm usually patching up stuff that the previous hack mechanic did. (hehe I feel sorry for the guy who has to follow me! ) I'm expecting to get a new circuit board for it, and think I should also get a light switch. That should fix all the lighing problems, but now the blower motor isn't working. I'll post a new thread for that one... I think what we have here is a bonafide gremlin! __________________ Ben '68 Chevy C10 Custom LWB 327/TH400 2nd owner '16 GMC Sierra 1500 SLE Dblcab 4wd 5.3

09-16-2002, 07:40 PM	#9
ThreeQuarter Senior Member Join Date: Jun 2000 Location: Texan in Iowa Posts: 2,523	Did some work on it this weekend. The headlight/blinker problem was due to a pair of crossed/twisted tabs where the wiring harness plugs into the cluster. One was hanging by a thread and came off while I was repositioning it. New printed circuit board from Kenny's: $50. Maybe that will fix the short in the cluster lights, too. The A/C problem is either the fuse box or the relay. He needs a new fuse box anyway so I'm already replacing it (got one for sale?), and I ordered a new relay from Kenny's just in case; $15. __________________ Ben '68 Chevy C10 Custom LWB 327/TH400 2nd owner '16 GMC Sierra 1500 SLE Dblcab 4wd 5.3



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