Help, I can't see speedo,rpm display!!

[73vettecollector]

Hi all. I just purchased a 87 convertible with 37,000 miles. Car is in incredible shape. The one problem I found is that the dash display does not light up. The electronic A/C display is nice and bright, but nothing on the dash.

During the day, I can see the speed, RPMs, and other display features, but not at night...

I checked the 5 amp fuse labled "gauges", fuse appears fine.

Any guidance? I don't want to spend a fortune paying someone to troubleshoot this, so I figured I ask the experts in this forum first...

Thanks,
David

 

[Im1ru2]

dash not lighting

If you can see the speedo and tach in daylight, it sounds like you Hopefully)
just need bulbs, do you have any manuals?

Jamm'in Jeff

 

[73vettecollector]

Jeff: No manuals yet (just got the car tonight). Bulbs easy to get too?

 

[FFAST87]

Yeah sounds like the four bulbs under the round metal pull out clips on your speedo bezel are all burned out. They are fairly easy to change. I just replaced mine. One was burned out, the others were just dimming with age as all halogen bulbs do. Best way to pull out the bulbs is slipping a peice of firm rubber hose over top of the bulbs and pulling it out. Its a little tricky, may have to use a thin needle nose to pull it out. I got the bulbs from a chevy dealer...about $14.99 each.

 

[jsinga]

Bulbs are expensive halogen bulbs. That dash is the only car listed using them.
Last ones I bought were @ $10 each.
You just about need to take the whole dash out to change them. If you can find a lamp extractor tool you can get them out with only the bezel off. Sometimes the sockets are cooked then you'll have to take the dash out to change them.
If you live in the south keep the dash covered up. The sun supposedly fades the LCD panels.

JS

 

[WhalePirot]

I guess we assume that the headlight knob is turned all the way up and the light sensor 'window' is not covered.

 

[Jeb]

Usually the bulbs can be removed from the front after removing the bezel and heat sinks over the bulbs. Get a piece of shrink tube with an ID about the same as the bulb. Slip the tube over the bulb and use a little heat to shrink the tube and the bulb will come out. As stated above, you might have to grasp the bulb with some needle-nosed pliers. To put the new bulb in, just use another piece of the same tube but don't heat it. BE SURE not to touch the bulb with your fingers as you will leave body oil on it and that will greatly shorten the life of the bulb.

To get at the dash innards, just remove the screws on the front and left end of the bexel, remove the headlight knob and it'll come right off, exposing the instrument panel.

The bulbs come with sockets. If you don't have to replace the sockets, you can do the above. If the socket is whacked, you'll have to remove the instrument cluster but that isn't hard either. Get thee a Helm's manual or some similar book and it'll show you how. It's only a matter of removing some more screws, moving the panel out and disconnecting the electrical hook up. Anyone with minimal mechanical skills should be able to do this entire job in less than 30 minutes or an hour.

Hint: You'll need a short handled phillips screw driver to get at one of the screws on the left end of the bezel so have one handy.

Good luck.

 

[Moonunit 451]

Just in case it doesn't go the easy way

 

[Jeb]

Been thinkin. (Dangerous)

What are the odds that all four of these bulbs would burn out at once? Could this be something else?

 

[Joe C]

Yeah sounds like the four bulbs under the round metal pull out clips on your speedo bezel are all burned out. They are fairly easy to change. I just replaced mine. One was burned out, the others were just dimming with age as all halogen bulbs do. Best way to pull out the bulbs is slipping a peice of firm rubber hose over top of the bulbs and pulling it out. Its a little tricky, may have to use a thin needle nose to pull it out. I got the bulbs from a chevy dealer...about $14.99 each.

go to a napa dealer for bulbs - same as the GM part (made by GE) - about half price. while you're at it, replace all 4 bulbs. nothing worse than putting in the last screw, and another bulb burns out.

 

[WhalePirot]

Been thinkin. (Dangerous)?

Actually, not? See my post above.

What are the odds that all four of these bulbs would burn out at once?

They might not have, "at once".

Could this be something else?

As I stated earlier,and as you can see the display in daytime, I believe the bulbs are working. HOWEVER, in dark conditions, a light sensor dims the dash.

Look carefully at moon's pictures, second from the bottom (above the circuit boards). Look just above and left of the opening for the speedo for a small squarish opening. It allows light into a photocell for the dimming function. The smallish photocell can be seen on the LCD assembly pic, in that pic.

This could be as simple as the 'window' being blocked. Does it have a wood (or other) fancy dash? Is there a blockge of the window (did you know there was one)? You can check the funxction by shining a light into nthis tiny window, in a dark environment.

Check that the headlight knob is rotated clockwise fully, (as on most other cars). If the dash does not respond to light, the photocell or the rheostat portion of the headlight switch may be bad. If the other dash lights respond to the 'rheo', it's okay.

 

[73vettecollector]

Thanks for the awesome tips and pics, will update

All:

Thanks for the awesome tips and pictures. This forum ROCKS. I will pull the dash apart tonight and see what the bulbs look like and post an update.

Yes, the headlight knob was engaged and turned to brightest (I watched the radio display increase in brightness).

No, I did not check the the light sensor. I don't believe it is covered but will check. (if its covered, won't the lights be on the brightest level???)

Thanks
David

 

[WhalePirot]

(if its covered, won't the lights be on the brightest level???)

No, dimmest, as it is trying to adjust for total darkness, when you want the dash the darkest.:cool

Yeah, greatest of forums. 99.9% of the folks stay on the helpful side of things. It really works well that way.

 

[Jeb]

WhalePirot, actually, I discounted the sensor since apparently he has NO background lighting since he can't see the LCDs at all. Nevertheless, it's something that could be whacked.

I just felt it odd that all four lamps would be kaput. I always forget that 37,000 miles on a 17 year old car isn't the same as 37,000 miles on a 2 year old car.

Hopefully, replacing the bulbs will do the trick.

Have you ever done the job of tightening the knuckle bolts on a tilt wheel and, if so, is it absolutely necessary to drop the steering shaft from the dash to do the job? I'd like to do mine but I don't necessarily want to drop the shaft. I've done it on other GM vehicles without moving the shaft and would like to think I could do the same with the Vette.

 

[WhalePirot]

Seems the easiest thing to start with here, is the light sensor, as the problem could be a number of places. I have seen other threads where a new owner did not even know about the self-dimming and bought the car with the hole covered. But then, this collector dude is one sharp cookie.

Have you ever done the job of tightening the knuckle bolts on a tilt wheel

No, sorry. I had play in my steering, noticeable during the 'morning sickness'. After replacing the expen$ive (even used) collapseable part and having the problem remain, I drilled through my old one, reinstalled it with a bolt through the hole, then got my refund.

Maybe you should start a new thread and ask?

 

[73vettecollector]

Dash lights...update at 9 PM

Hey guys, thanks for the tips. Per your tips, I removed the dash bezel to inspect the bulbs. I pulled the first bulb... it was shot. I pulled the second bulb...it was shot.

Next, with two remaining, I decided to remove the entire console. I took apart the back of the HUD, removed the first layer of CPU and got to the bulbs and sockets from the back side.

Turns out that all four bulbs were blown. I figure after 17 years, the first owner probably noticed them going one at a time... lazy...

Bulbs are: GE-882

Will get the bulbs from either Napa or the dealer.

Anyway, I will keep you all updated as I get them back in and put the dash together. The pictures and input saved the day. Whole job with your guidance took an hour.

Shack

 

[Moonunit 451]

GREAT JOB SHACK! Prepare to have your eyeballs blown out :L As has been discussed, I seriously cosidered covering the sensor after repairing my dash, so I could dim the lights ---- during the DAY Definately took some getting used to, but I managed

 

[Rocky Ak]

if I use a lighter in front of the opening to the photocell and my speedo and tach. do get brighter (enough to see at night) does this mean my light switch is bad?

 

[redc4corvette]

Try this site http://www.batee.com/corvette/dcrg/problems.shtml

 

[Rocky Ak]

thanks redc4corvette. excellent site.