Just in the last month or two the tripometer / range readout started to freak out. See the below pic... sorry for the crappy camera phone picture.

I read a lot about the digi dash in these things having to be serviced... is that the case here? I saw that ecklers does it for 500 bucks or so, is that the going rate?

 

You likely have a bad LCD pane and these can be purchased for about $70 to $150 on ebay. It isn't very hard to replace the pane if you want to give it a try. There are driver integrated circuits to control the bars on the LCD pane and it is possible that the IC is defective, something you wouldn't want to find out after replacing the pane. Ecklers is on the expensive side and there are a number of approved factory service centers that overhaul dashes and usually charge $200 to $350.

 

A fellow forum member scarabexc@aol.com did mine 2 yrs ago. He still does em.

 

We have at least one supporting vendor that does them. Steer clear of Ecklers, too expensive.

 

We do them for $379 (with core), but not every C4...

92-93 LT1 CLUSTER RESTORATION SERVICE

95-96 LT1 CLUSTER RESTORATION SERVICE

 

I'd love to get a solid thread of repairing these things going since I imagine most of the issues are fairly simple and don't require the fancy GM test equipment.

I don't have any good answers for the original poster's problem, but for any others with dash issues - here's what I've been dealing with...

My odometer and tach went out on my supercharged 88. The odometer just quit turning, and the tach LCD is so bright in the middle you can't see anything being displayed. I did a little research and found that the LCDs go bad and you can buy replacements on ebay for $100. The problem is, as I was driving home one day I hit a large bump on the highway and the tach came back, which as far as I know would negate the 'bad LCD' theory and point to a wiring issue. It only lasted a little while though and it's back to being too bright in the middle.

I swapped the digital dash clusters from my supercharged 88 to my NA 88 which has a perfectly functioning cluster in order to eliminate wiring harnesses as being the issue. The 'bad' supercharged cluster tach still had the same problem and the odometer still didnt turn, though the digital trip odometer feature works fine as it does in it's correct 88.

I've taken both clusters apart (circuitboards and all...it's not tough...just lots of screws but they're all the same size) and found that my NA 88 cluster had been serviced before I purchased the car. It had a new circuitboard on it that appears to be a power supply board (does anyone know for sure what it powers? I assume the lamps or odometer motor). For those who have yet to take one apart, there are 3 circuitboards. Two large ones that connect together with a pin connector and a small one, fastened to one of the large ones and connected with a soldered ribbon cable. Once you have the ciruitboards out, you can easily get to the 3 lcd panels to replace them, or get to the light bulbs that illuminate the LCDs and turn signal/hi-beam indicators.

I removed the odometer and applied 1.5v, then 9v, then 12v to it to see if the motor might be bad but the motor didn't turn a bit. It is a stepper motor which I know nothing about so maybe just applying DC voltage to it isn't a good test. Anyone know? I don't NEED to repair it, but being a 30,000 mile C4 in mint condition, I would like to be able to sell it for a good price with an honest odometer reading and an honest face. The motor tested 170 ohms which I would think is ok. So...I either have a bad motor or a bad output from the circuitboards to the motor, neither of which I know how to test, nor can I find any info on testing.

I also removed the tach LCD and it is clear in the middle, with the liquid collected around the edges. This seems to point to 'sun fade' as I've seen it described so it would appear that I need a new LCD. However, this doesn't explain why when I hit a bump it displayed normal for a while (although it hasn't done it since then and I've hit numerous bumps and RR tracks). It also seems strange that this could be sun or UV related as the car has a fiberglass top and always had windshield shades and/or a cover on it if it was outside. The contacts for the LCD's are a fleshy looking foam rubber material with the conductor sandwiched in between. I would like to use contact cleaner on these goofy looking contacts but am concerned about it eating away the foam. Any advice?

-Eric

 

Yes, Batee.com has an extensive write up on exaclty how to fix your DDash.

I followed the instructions and after about 4 hours the job was done. Most of that time was spent getting the right size nut driver to disassemble the boards.

This info is posted at least weekly and if you get all the bulbs you'll spend about $45 at Napa...but there is another recourse that has the bulbs for ~$2.50...that info is posted probably monthly...but I'll allow you and others to practice using the search function to find out how to save $35 on bulbs.

Going to Batee.com saves you ~$300-$500

 

Most of the time, when the Tack is wacky acting there is a short in the coil. Try that