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Hi,
Before I order and replace the printed circuit board, I thought I'd get some opinions or thoughts from the group at large...
Everything seems to work except the bottom two gauge lights (oil temp and voltage) and one in the middle. The top lights do work and when the dimmer is all the way up its enough to light up the bottom, barely.
I pulled everything, replace the lights with new tested working lights and still same issue. The circuit board is original to the car and I can't really tell nor have the experience to test the board itself... All other lights and interior functions work EXCEPT that the courtesy lights to NOT come on when the light switch is turned all the way (counter clockwise) - not a huge deal, but I don't know why the bottom few lights on the gauge cluster will not work. The gauges do... Should I replace the printed circuit with a new one or is there something else going on???
It sure sounds like one of the copper traces on the board is broken. If you hold it up to some light you'll most likely be able to see the problem place.
Your courtesy lights not coming on with the dimmer turned fully left is unrelated. All the switch does is provide an alternate connection to ground for the circuit. Any problem with it should be obvious.
Pull the cluster and either test continuity of each circuit from the PCB connector to the lamp, or power up the circuit individually to see if it's bad.. I'd do this before I purchased anything. So if you put power to the top finger on the left side and then ground all the lights should light up in your hand... this will verify the pcb one way or the other. But take note, the three lower lamps use a ground through the amp gauge and the upper lamps use a ground coming from the top right top finger... you'll have to ground both. If it pass's this test then the issue is elsewhere.
Issues that plague the pcb's would include the fingers where the connector plugs into coming un-laminated and when this happens its possible one could be touching the other. If a circuit is blown it'll show up just by looking at it.
Last edited by Willcox Corvette; Aug 6, 2016 at 11:11 PM.
Pull the cluster and either test continuity of each circuit from the PCB connector to the lamp, or power up the circuit individually to see if it's bad.. I'd do this before I purchased anything. So if you put power to the top finger on the left side and then ground all the lights should light up in your hand... this will verify the pcb one way or the other. But take note, the three lower lamps use a ground through the amp gauge and the upper lamps use a ground coming from the top right top finger... you'll have to ground both. If it pass's this test then the issue is elsewhere.
Issues that plague the pcb's would include the fingers where the connector plugs into coming un-laminated and when this happens its possible one could be touching the other. If a circuit is blown it'll show up just by looking at it.
Thanks! I think I am going to just replace it. Looking a little further discovered some delaminated areas. Cant tell if the line is broke. Suppose power will tell...I know Willcox sells these...any recommendations, or can you tell me what separates yours from another vendor? I ask because there is a company claiming to have a thicker reproduction, which I thought might be better...but I don't know? You guys have some great videos which have helped me already!
Thanks! I think I am going to just replace it. Looking a little further discovered some delaminated areas. Cant tell if the line is broke. Suppose power will tell...I know Willcox sells these...any recommendations, or can you tell me what separates yours from another vendor? I ask because there is a company claiming to have a thicker reproduction, which I thought might be better...but I don't know? You guys have some great videos which have helped me already!
I've never had the first issue with the one that we sell, they seem a bit thicker than the OEM but I've never mic'd them. But I've hand nothing but success out of them... Thank you :thumbs -Willcox
Mine had also delaminated in places and had a fried trace with duct tape and a direct wired connection as "repairs". I made some repairs of repairs but they proved unreliable.
Finally I bought a replacement from Willcox and I will sincerely say that it seems to be of a quality that will outlast the original. It is "lighter" but plastic layers are completely different and can scarcely be called a "lamination" as the copper traces are truly encapsulated and also embedded (not simply adhered) at the contact points.
Thanks guys! One thing...mine has the oil temp gauge vs. the clock. It's got what appears to be tape over the clock node/finger. There is a prong connector there. I'm assuming that if I bought a new one that I'd just put tape over the clock node/finger like it is now??
@willcox corvette I sent an email request for sales/pricing on the PCB and have not heard back...it's been a few days? The reason for the request is that I could not find that you offer this for the 81??
Had this car for a while and gauges worked randomly. This is the first time I pulled out the gauge cluster and look at this fiasco. LOL!! Anybody have an idea what they were doing with that yellow wire? That is the fuel gauge its connected to.
Last edited by cu79vette; Mar 29, 2019 at 04:59 PM.
Reason: Add to post
Had this car for a while and gauges worked randomly. This is the first time I pulled out the gauge cluster and look at this fiasco. LOL!! Anybody have an idea what they were doing with that yellow wire? That is the fuel gauge its connected to.
That looks a lot like the ones I replaced in my '79 - there was a few jumper wires soldered in also!
They did that because the copper was gone that ran to the gauge. The "fingers" where the harness
connector plugged in were all mashed together too - surprised it didn't burn out the gauges, but they all work now.
Thanks!! That was my assumption. I am replacing the PCB tomorrow. I think I may have an issue with my speedo/tacho PCB also. My turn left turn signal light will go from a flashing light to a solid light at times. Will check the flasher first though.
Thanks again!! Replaced the PCB and my fuel gauge and voltmeter work again. I will test the oil pressure gauge (saw a good thread on this). The clock ... really don't need but would be good for looks and since I am in there may just get it right.
When you replaced your PCB did everything come back instantly or did you have to play with it some. My lights are shaky ... I know I have an issue with my headlight switch but I think the issue is unrelated. I've hook it up the gauge cluster and taken it off a few times and different lights work each time. I may get new light bulb sockets for peace of mind. Any thoughts or suggestions, please let me know.
Awesome! If you don't get the clock working, unconnect it from the PCB and put electrical tape on the contacts on where it would hook up - a bad clock will run down your battery.
The little wires on the dash bulb ends get misaligned and don't make a good connection - while it's off you may as well replace them so you don't have to take it off again (peace of mind).
I did have to replace my headlight switch as the rheostat for dimming the dash lights was burned out - and now everything works!
I hope your luck is as good!
1981 Printed Circuit Board - Replace?
You guys have some great videos which have helped me already! 
