rough

So I have been chasing this grimlin for around 2 years now, Searched and searched, thrown parts down, hours, money, sweat.

Here is my Problem.

I Switched out my old frayed speedometer cable "old 2 piece into the 1 80" piece." Went smooth as butter! Cleaned up the back of my 145, added some fresh lube to the cable, installed the cluster, pushed the speedometer cable till it snapped into its ring, installed the last few bolts and faceplate. "Ive done this before installing the 145mph speedometer from the 85mph."

Insert the key, fire it up! Take off and man the speedometer is nice and clean, no fluctuations, no bouncing, perfect!

Off to work, got off at 11pm, it's so dark, so I turn on my headlights and Woa! My tackomoter jumps, oil gauge goes all the way up, battery voltage drops to around 12v "normal is around 14" but 12 is fine "subs will make it drop below this on big thuds which don't do much but dim the headlights."

So I turn on my turn signal to merge onto the freeway, and I see my Tachometer jumping up and down with the turn signal light, it goes up when the lights on. I adjust the dimmer, then the slightest touch the tachometer peaks at 7k, I pull over to figure out whats up.

I turned the dimmer all the way down, killing all inside lights, the tachometer works perfect, but oil is still maxed.

I use turn signal takes about 1 second to flash, perfect. Turn on lights, use turn signal takes about 5 seconds to flash, not good.

Any adjustments on the dimmer will make the tachometer do various things.

I took apart the cluster again, checking the board for cracks, reading about the flaps not making good contact, I tried a variation of the matchbook trick, but using thick paperboard, bent in a a triangle shape, used 2 per side.

I see no issues with any of my hardware, So i'm looking at other possibilities, grounds. Clean them all up, sanded each.




I've even pulled the metal tabs up some on the backing of the dash, they are pretty strait, and seem to make a good contact. I pulled the tachometer to make sure, seated cluster, and could see the right side at least seat it self with the folded board helping clear up the tolerances.

When I have the headlights on and the dimmer lights on I will push on the cluster different directions getting different effects from the connections on the back not connecting properly, when I snug it all down, still with the issues like it's totally installed I noticed the top right 3 bulb's for the back-lights above the tachometer do not work. Replaced them, same effect.

Using my lighter or flash light sucks to see how fast your going, I don't use the dimmer "all the inside lights" to avoid any fire hazard I may cause except when i'm in the garage tinkering with it.

Thanks for reading my story, any input - input-ed would help greatly, As I plan for another road trip to Florida here soon, "Made 4 round trips to California and back already."

rough

bump any ideas
Tachometer fluctuates while turn signal is on no matter what, I do not see any damaged wires, gonna double check all grounds again.

clutchfann

mine has a similar issue, i bought it with a pust start ignition and when it turn on the lights the dash lights go crazy. one time a friend actually hit my CD player because the cd wouldnt come out (its a POS) and the das lights and tail lamps went out. i had to remove the cd player and some of the wires in the back were exposed so i taped them up and changed the fuse. problem solved.

petrolhead

I would say you have a bad ground somewhere. Mine did that years ago, I removed the cluster, cleaned the contacts, replaced bad bulbs with the correct ones, tested the connections with jumper wires out of the car, and its been fine since.

rough

Ive not recently checked behind the radio, but defiantly will check that out! I know its gotta be a wire, bad ground some where as Ive used a multimeter and checked the board and had no issues.

Half tempted of making a bunch of lines with gator clips and start attacking them up like it would be sitting in the cluster, that way I can be sure.

Gonna go clean some more connections, and ponder on making cables!

rough

Gonna try and locate another board just eliminate the issues, spent hours last night with a testing light, and jumpers setup on a battery testing all the components, I found a few cracks in the copper traces, and just wear and tear I just want to replace it.

Edwardgp

Some PO just butcher the wiring on any car they get there hands on.

rough

Yea there is a little bit of it, will be nice to one day rid all the wiring and go bare min.

87firebird96

Gotta question my rear turn signals and right turn signals and hazards don't work but left one does right one makes my gauges go nuts and ideas

bigal55

iTrader: (1)

For problems such as these, you need to check your grounds between the engine, frame and firewall. When lights exhibit these symptoms, it is because the power is fluctuating or there is a bad ground. The grounds not only at the dash circuit board but also the main system grounds. It's easy to overlook system grounds as the problem seems to be local to the dash or tail lights but the circuit needs a good complete path back to the battery so any corrosion or loose connections along the way can cause all sorts of weird problems. HTH!

87firebird96

Ok where would I find these ground connections under neath the hood

bigal55

iTrader: (1)

Your tail lights probably just ground to the body or a frame member pretty close to where they are located as GM tried to save as much money as possible when building these cars (less wire, lower cost). Also, you should have a ground strap from the engine to the firewall. Because the body is mounted on rubber mounts, you need to be sure you have ground straps from the engine to the body (usually the firewall). The engine is also mounted with rubber mounts, so the engine to frame should also be grounded. Don't forget, these cars are 25 years or older so corrosion at body and frame points is common.

Scorpner

iTrader: (4)

I know that Camaro headlight grounds are forward and in-between the radiator and battery. (Two wires iirc.) Firebird should be similar but possibly on either side.

Bullydawg

iTrader: (7)

Ever figure this out? I had this issue, and am in the middle of a 4th gen dash swap and I think this is causing bigger issues with he Serial 32 data wire.

GoStumpy

Bumping and old thread because my car has these EXACT symptoms... gauges are fine, I turn the headlights on and the tach, oil pressure, and volt gauge goes crazy... if I turn up the illumination the tach will rise equally... I took a video:


Wondering what grounds to start checking? Obviously it's a ground issue....

Cheerio

iTrader: (1)

try pushing on the dash cluster.ive had a similar issue and it happened that I didn't reinstall the cluster "correctly". going over bumps would make it go all wonky or dim some of the lights. sometimes the turn signal would just stay solid. high beam indicator would come on. I just pushed on the cluster when it was acting up to see if anything happened. then all my gauges would go to "normal".

Custommaro

I had this exact same problem. Turn on headlights and all the gauges would go backwards and no dash lights except the blinkers would stay lit. For a while I could fix it by hitting the dash in the right place. Got sick of doing that so I ripped everything apart. I pulled the cluster and headlight switch, took the switch apart and tested it and found nothing. Was thinking it was a bad ground and maybe a backfeed issue so I checked and cleaned up all the grounds. Put everything back together and it was even worse. Now, no blinkers at all, no hi/low indicator and gauges still mess up when headlights are on. I tried plugging and unplugging the cluster with the headlight switch on and no change. I spent hours on this and it was only getting worse. Was starting to think I messed up the printed circuit board taking the cluster in and out so many times. Frustrated, and in a last ditch effort, I put everything back together and YOU KNOW WHAT FIXED IT? I WIGGLED THE WIRES GOING TO THE PLASTIC BLOCK THAT PLUGES INTO THE CLUSTER BY REACHING UP BEHIND THE CLUSTER, LEFT HAND SIDE. DID THIS WITH THE HEADLIGHT SWITCH ON AND HIGH BEAMS ON, SO I COULD SEE ANY CHANGES IN THE CLUSTER. One by one, by moving the wires and the block a little, everything came back to life. Blinkers fixed, hi/low beam came back and backlights all worked!! I believe that the loose fitting wire block and the printed circuit board were simply out of alignment. I could not believe it was this simple!!! I spent hours on this and finally was able to fix it in 15 seconds. I hope this helps someone, I saw many other threads about this with the same problem. I cannot believe that's all it was. WTF and thank God!! Works perfect now

MacRocZ

Still working for you?
I've been known to fix something and think that it solved it, but it peaks it head again.

Also what is this plastic block you speak of?
I'm wondering if it is only on certain years.
Mines is an 89 IrocZ

MacRocZ

Well Sure enough I pressed on the lower right side of instrument cluster, bam! Its back to normal!
If i release it, it goes back to acting up. Time to take it off and check it out!

WILL85IROC

im having similar issue, im going to check ground straps tomorrow!!!