Gauge cluster trouble

[bugmasta]

So here is the deal, with the lights off everything works fine. But as soon as I turn the lights on or even just the running lights, both turn signals illuminate, all gauges go dead, and no backlighting for the gauges. Any suggestions? This just randomly started the other day. Everything was working fine then all of a sudden this crazy thing started.

Checked the fuses and can't find any that are bad. Only the turn indicators in the cluster light up, no actual turn signals on the outside of the truck light up. If I hit the signal switch, the opposite light in the gauge flashes but the correct tail light blinks.

It is the weirdest thing and I can not figure it out. Please help, hopefully someone else has experience this.
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[Longhorn 70]

It sounds like a funky ground or open trace on the printed circuit to me. Anything different when you step on the brakes?

[bugmasta]

Nothing changes with the brakes. Is there a ground on the back of the cluster somewhere that could have come loose?
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[Longhorn 70]

The Wiring Diagram may help.

[71K20chevy]

Run a ground and see if that fixes it...

Here's a tip of advice that I've learned...when electrical components start acting weird, ALWAYS run a ground first, it usually solves most problems..

[bugmasta]

Originally Posted by 71K20chevy

Run a ground and see if that fixes it...

Here's a tip of advice that I've learned...when electrical components start acting weird, ALWAYS run a ground first, it usually solves most problems..

may be a dumb question, but i suck at electrical stuff. what is the best way to "run a ground"

i understand how to create a ground, but where on the gauge cluster should i run the ground from? should i just run it off one of the threaded posts on the back side of one of the gauges?

[71K20chevy]

There is a single bolt (1/4" if I remember correctly) on the backside right by the oil gauge, it's a perfect spot to run a ground. You can then run the other end of the wire to where you know you have a good ground.

Don't run it to one of the threaded posts on the back of the gauges..you could possibly burn them up.

[bugmasta]

Originally Posted by 71K20chevy

There is a single bolt (1/4" if I remember correctly) on the backside right by the oil gauge, it's a perfect spot to run a ground. You can then run the other end of the wire to where you know you have a good ground.

Don't run it to one of the threaded posts on the back of the gauges..you could possibly burn them up.

perfect, gonna try this as soon as i get the kids in bed!

[Coley]

Ok, here is something I want you to do:
Find or buy a good 1157 turn signal/running light bulb. Then check this (new?) bulb visually to make sure its inner 2 circuits are intact and that this bulb works well and properly.
Then, check all (4) of your corner signals that use this type of bulb by substituting this good bulb against the one that is in there. When you remove these existing bulbs during this test...visually inspect them to see and ensure that their 2 inner circuits are intact.
Now, the backstory on this is that sometimes when an 1157 bulb goes, what happens is that one of its inner circuits burn out and sometimes end up curling and touching the other circuit within the bulb. This creates a completely new path or circuit that can really mess up the lights within the vehicle....running lights, signal lights, etc.
The condition that can often result is exactly what you are describing (....ask me how I know)
Give it a try and keep us posted on how things work out!!
Good Luck
Coley

[magwakeenercew2jh]

You already have gotten a lot of good advice.

I'm no expert. But I was in my dash today.

Here's a thought: You have to keep it simple. Don't start doing a bunch of stuff at once. If everything works with the lights off, then (after running a good ground and it's still f.u.'d), the first place to look...
....Oops! I should say the *second* place to look...The FIRST, is to copy bthe wiring diagram ...a GOOD copy..The one Longhorn sent you is great...print it if you don't already have one.

Okay, the second place to look is the light switch.

Everything works *before* you play with it, right? So, if everything works with the light switch "off" when the truck's ignition switch is in "on", "acc", and "off" position (and, maybe even while running), and the
gremlins attack the same spots and in the same manner when you turn (pull) the light switch (or out only one click to the "parking mode") while the ignition switch is in the "on", "acc", and "off" positions
(and maybe even while running), then you've started the diagnosis, Doctor.

Barring the first visual lookey-see that would tell you nothing under there is obviously loose, fried, etc., I'd go with the ground, study the wiring diagram (in your sleep), and then pull the light switch.

I wouldn't suggest doing it the way I do it...That is, find the most expensive part. Thank the good Sellers on the Forum (first choice), or push "Buy It Now".
Wait for the mail.....Get the part. Put it in....."Sh*t!" Find the second most expensive part....Okay, you got the drift.

......Nope. Don't do it like that.

But, after I tested for strange readings all over the place, I *would* look at getting another light switch in order to rule out that part. Not my method. Smarter. The switch is about the eighth most
expensive part up there.

[bugmasta]

Originally Posted by Coley

Ok, here is something I want you to do:
Find or buy a good 1157 turn signal/running light bulb. Then check this (new?) bulb visually to make sure its inner 2 circuits are intact and that this bulb works well and properly.
Then, check all (4) of your corner signals that use this type of bulb by substituting this good bulb against the one that is in there. When you remove these existing bulbs during this test...visually inspect them to see and ensure that their 2 inner circuits are intact.
Now, the backstory on this is that sometimes when an 1157 bulb goes, what happens is that one of its inner circuits burn out and sometimes end up curling and touching the other circuit within the bulb. This creates a completely new path or circuit that can really mess up the lights within the vehicle....running lights, signal lights, etc.
The condition that can often result is exactly what you are describing (....ask me how I know)
Give it a try and keep us posted on how things work out!!
Good Luck
Coley

all my turn signals are LED. wonder if those are the issue. weird thing is it just happened out of the blue. nothing changed nothing new. literally drove to my parents, parked, came back out to leave, and no lights except for the mildly glowing turn indicators on the dash. so weird. headed out to try the grounding trick.

[bugmasta]

couldn't find the post to the right of the oil gauge. tried using aligator clips on a couple different spots on the back of the cluster and no difference. my guess is it is something in the actual headlight switch.

here is a pic of the back of my gauges, where should i place the ground?

[luvbowties]

here is a pic of the back of my gauges, where should i place the ground?

Run a good ground to bolt labelled "HERE"--lower right, in pic below.
sam

[luvbowties]

[QUOTE=luvbowties;5898330]here is a pic of the back of my gauges, where should i place the ground?

Hey bugmasta, look closely at a suspicious area seen in the picture labelled "CHECK". Looks like printed cct may be burned--in the pic, at least.
sam

[71K20chevy]

Here I have circled (very poor circles, I'm bad with editing pictures ) a couple of ground spots.

The circle on the right is the one that was posted above, and the circle on the left was the oil gauge one I was talking about.

I personally prefer the oil gauge one because there's more room for me on that side.



Of course, you can add them to one of the screws on the out edge, but that'd be a pain in the butt trying to get undone if you have to take your cluster out.

[bugmasta]

Ok, those are the screws that I tried last night using alligator clips with no luck. Today when I have more time and room to work I will put the screws and put the ground under the screw and tighten it down.

The circuit board does not have any burnt spots, just the crappy cell phone pic. I also tested it with 2 different clusters. Had and extra set from a parts truck and it did the same thing as the one that has been in the truck. So I am starting to think more and more like its the actual headlight switch. I am going to pull the one from the parts truck today to see if that fixes things. Thanks for all the support and advice guys.
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[bugmasta]

Swapped the light switch and the entire gauge cluster and still have the same problem. Unplugged all lights and still have the problem. Tried grounding it every place I could think of and nothing. This is really starting to piss me off. I can't figure this out and it just randomly started. Nothing was changed to cause it. I hate electrical issues. Any new ideas?
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[71K20chevy]

At this point I'd check the pigtail harness coming out the back and all the rest of the wiring to make sure it's intact

EDIT-I forgot that if your front marker lights are disconnected, that causes the turn signal indicators to glow. But that doesn't explain no gauges...


I'd say also try replacing your blinker, they're pretty cheap if I recall.

[magwakeenercew2jh]

Originally Posted by bugmasta

Swapped the light switch and the entire gauge cluster and still have the same problem. Unplugged all lights and still have the problem. Tried grounding it every place I could think of and nothing. This is really starting to piss me off. I can't figure this out and it just randomly started. Nothing was changed to cause it. I hate electrical issues. Any new ideas?
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You changed more than one thing. The light switch AND the cluster. What else did you do?
Is the problem still that when you pull the switch, you get the gremlins? I picked up something in an earlier post. You wrote that the lights on the dash for the turn signals were glowing when the problem first arose. Any other hints? Are you working with the dash in or out of the truck.

Maybe you could list what tests you made under what circumstances (key on or off, etc.), and spell out the problem again.

Don't get pissed. It doesn't care. And, in my experience, being pissed is a block wall to climb over. Maybe use that energy to try to remember ANYTHING that may have tipped its hat before the primary symptoms showed up.

BTW, I got pissed yesterday when I realized that the fuse I put in line for the electric bucket adjustment power under the carpet. I was diagnosing a different issue and needed the seat back further. I found the hot line and before I cut it to see if I had juice, I checked the fuse box and connections at the box. All were good. Then, I realized that I needed to turn on the key.

One thing at a time.

[71K20chevy]

Originally Posted by magwakeenercew2jh

BTW, I got pissed yesterday when I realized that the fuse I put in line for the electric bucket adjustment power under the carpet. I was diagnosing a different issue and needed the seat back further. I found the hot line and before I cut it to see if I had juice, I checked the fuse box and connections at the box. All were good. Then, I realized that I needed to turn on the key.

One thing at a time.

Kinda like that time I couldn't figure out why my truck wouldn't start and it was because I left it in reverse

[bugmasta]

Here is what I have done. All things were done independent of each other. Made one change and then undone it to make the next change.

Swapped light switch
Swapped gauge cluster
Unplugged running lights
Unplugged head lights
Unplugged tail lights

All the above were tested with the key on and off. All tested with brakes on and off. All were tested with a ground wire attached to the cluster and to the frame.

This literally happened without making any changes. I drove to my parents house, went inside for 30 minutes, came outside and the gremlins were in the dash. That's all I know.

I will try changing the flasher tomorrow. They are cheap at about $3 so it's an easy test.
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[bugmasta]

Any new ideas? Nothing is working so far.
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[magwakeenercew2jh]

Not that it'll do you any service, but I've been thinking about this all day.

It's almost 12:00.
More tomorrow.

[bugmasta]

Originally Posted by magwakeenercew2jh

Not that it'll do you any service, but I've been thinking about this all day.

It's almost 12:00.
More tomorrow.

Thanks man, really appreciate the help. I've got an electrician coming tomorrow to do some work on my house, may have him take a peak at it to see if he has any ideas.
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[magwakeenercew2jh]

Okay....I checked your build page and see your rig is running the same dash...meaning lights and wipers on the left...as mine.
Looks like you are.

I see from, at the point of the pictures you posted, that, the dash face and gauge cluster was placed up in the dash with no light switch
or wiper switch installed.

I suspect that was part of the build pics, but all was done and in and working before the Gremlins struck.

The picture you showed with the printed circuit showing and the dash out. Was that earlier or is it out now for the fix?

I see you put Vintage Air in. And, I'm guessing you used the original printed circuit from the truck...Although I'm not smart enough to
cross-reference the numbers that show on the back on the picture, I'll figure the Printed Circuit plug is properly "pinned" for that Printed Circuit.


A couple of questions first:

Did you add or take anything away (electronic) I missed. And is the main under-dash harness, fuse box, and all the other stuff under the dash the same as it was when you got the truck?

I didn't understand when you said you changed the gauge cluster....You mean you dumped everything behind the dash face...gauges and all? Or just the sheet metal?
Or the sheet metal and printed circuit....?

Once again, is the dash OUT? Or, are you willing to get under there with a test light and maybe a multi-meter while it's still in? That's be a P.I.A., in my opinion.
At the least, you'd have to move the driver's side V/A duct out of the way to get at a couple of things to test.

Next question...and I'll tell you why I ask that later....Do your amp meter, temp gauge, fuel gauge, and brake warning light in the dash work?

A couple of things I'm looking at...Remember, I'm chiming in because I've been in there and had a bunch of issues in a couple of builds, butt I'm no expert......
...I think you said everything "goes dead" on the dash when you switch on the headlight switch. After you changed out the HL switch, and the same crap still exists? I HATE assumptions.
But we have to assume, for this exercise, that the newer H/L switch wouldn't manifest the same problems as the other one. So we'll count that part as in good working order.

So, here's the thought....

The Gauge Feed (S/B purple) running into the #3 at the gauge cluster plug, powers the temp gauge, fuel gauge, brake warning light with 12v. I believe each of those have individual
(and in the case of all but the brake warning lights), different *variable ohms* grounds.

I would test that power feed with a test light (at least) with the key on and off, and with the light switch off and on. Of course, you should get power there only with the key on and, with the
tip of your tester on the #3 tab and the other end clipped to ground...making sure that the cluster is grounded. Now, none of that is necessary if those gauges work. You'll KNOW you are getting
power at 3 if those gauges working! But you said "all gauges go dead" when you pull on the H/L switch.

That's a test. Not a fix. But you have to do the test first.

Next, you say the dash lights are all dead once you pull on the light switch. And the turn signals "glow".

These "Cluster Lights" get their 12v power from #8 at the P/C plug. I'd do the same test as you did with the fuel, temp and brake light power line in.
Ign key on or off, you should have power when the H/L switch is turned on...even if it's only switched on to the parking light "first click".

I'd bet you do.

Why?

Because I think the ground that grounds all of the Cluster Lights (should be coming off of terminal #7 of the P/C) is somehow feeding the housing. In some sort of high-resistance way.
But enough to send some juice to the turn signals and make them glow. Now, that's a diagnosis. Maybe a bad one. And, probably one that is too early.

Here's my road map:

I would pull the cluster once I had it in a position that is was consistently demonstrating the gremlins....Bye-bye (unscrew) the oil pressure line and speedo cable (no starting the truck for a while now)....
Leave the Printed Circuit Plug plugged in, the headlight and windshield washer switches replugged in (you might have to make sure the H/L housing is grounded if you just let it hang down...I'll check that....),
and the banana feed from the column.

I'd make sure the dash cluster was grounded and then check it again to make sure the same crap was happening. Then I'd do the above tests.

I'd "wiggle" the P/C plug.

I'd look VERY carefully at the printed circuit to check for any flaws.

If I had juice at the #8 terminal with the light switch on at least one click, I'd probably run a temp (testing) ground from #7 to the truck.

Oh, yeah. You have to make sure the rheostat on the H/L switch is twisted high enough (all the way) so that there's juice coming to the Cluster
(or "Dash") Lights.

SIDEBAR:
I didn't ask, but does your dome light go on? It's a good test for the switch and for everything else, too. And, it's wiring can be a source of the
problem, too.

But, that may be the next step. There may be more in between.

You'll get it.