Hi Guys!!

This will be my third time to post this question, "Can I repalce the circuit board on my tach at home, and how do I go about doing it", and the only answer I have goten so far was to learn to live with it.

The last posting of this question, I received a reply saying that it was a difficult job, and I should just learn to live with teh broken tach. Obviously, you can't drive a C3 with a dead tach!! Watching the sexy guages is part of the fun!!

This is a 1982 stock C3 and the tach is laying all teh way over to the far right hand side, like it's pegged out. Every once in a while it will jump back a little, usually while you're cranking it over. I was told this indicated a bad circuit board. However, I have never tried to replace one and wanted to know exactly what was involved.

Thanks in advance,
DT

 

Ecklers sells the replacement circuit boards kits. I imagine instructions come with them.

http://www.ecklers.com/dept.asp?dept...LQKEVMRNX6C2W2

 

If it's anything like a '75, the board attaches to the back of the tach. This means you have to get behind there. That is the hard part.

 

It can be done if your handy and have time. No special tools or knowledge required. I did it on my 76, should be similar.
It went something like this. (From memory so...)

Remove at least one sun visor and the winshield panel trim on that side, I did the right. Both would be better, but I was lazy.
Remove the dash panel screws across the top.
The dash panel should be loose and you should be able to remove it. If its not loose, look for more screws. when you got them all, work it around the winshield pillar on the side that you removed the trim. You might have to bend it up a bit in the middle to get it around the windshield frame. Mine went back into shape. Watch out for the speaker wires. Disconnect them.

Remove the drivers side dash screws across the bottom, in the door, and in the console by the gauges.

Not sure if your year has the trip reset and headlight vacuum switches at the bottom, if so remove them and the bracket they are attached too.
Drop the steering wheel as much as you can.

The speedo cable has a spring clip at the back. You need to push on it and pull the cable at the same time and it will come loose.

With the dash panel removed, you should be looking down on the gauges. Pull the lamps and connectors out. Bend the harness clips and push the harness back over the gauges. Pull the entire dash panel forward so you can see the back of the gauges and remove the gauges. Take it inside and replace the circuit board. DO NOT TOUCH THE FRONT OF THE GAUGES. The ink may smear.

The new board can be bench tested and calibrated before you put it back in. However, setting the pointer and calibrating can be a bit tricky if you do not have electrical expertise, but it can be done using a modified AC adapter.

Takes about 3-4 hours to disassemble dash and remove gauges if you've never done it before. Half that time the second time you do it.

Iv'e probably missed a few steps. If the electrical part is an obstacle, there are members that can replace the tach circuit board and set it up for you for a nominal fee (MikeMercury is one).

Good Luck