Chevy Astro and GMC Safari Forum banner

Dash light went out

2K views 11 replies 4 participants last post by  RECox286 
#1 ·
So yesterday I had most of the dash off to do some plastic renovation, this included the dimmer switch and the instrumentaion cluster (-87 with speedo cable). Everything was working as it should before i had everything removed.

When I was done with what I had to do I put everything back together carefully just to find out I had no backlight in my instrumentation cluster anymore. All indication-lights were still working, same with the interior lights. Just the backlighting. Took the instrumentation cluster back out to check and all 4 bulbs were burned out. So I replaced them, checked the fuse (wasn't burned) and thought I'd fixed it, but no. Still no backlight. I have had the cluster out several times, I've put oxide cleaner on the electronic connector on the back of the cluster, I've been really thurough putting it in but still the backlighting is not working.

Everything was working just fine before I removed it the first time. And how is it that all 4 bulbs had burned out from doing this? Short circuit somewhere?

It's really annoying not being able to see anything driving when it's dark.
 
#2 ·
Is it possible that the head lamp switch dimmer got moved towards "dim" or that the electrical connector got torn ?

Uncle Bob
 
#3 ·
RECox286 said:
Is it possible that the head lamp switch dimmer got moved towards "dim" or that the electrical connector got torn ?

Uncle Bob
The actual dimmer "slider knob" never worked. Only when I flicked it all the way to the left the interior lights in the roof lit up. The actual dimming of the dash lights never worked. The backlighting of the dash cluster was just always on as soon as I pressed the dimmer switch to turn headlights on.

What's weird is that all 4 backlight bulbs were burned out. I noticed when I took the van for a drive yesterday that my left indicator-light stopped working too. Something is either rubbing and short circuiting the bulbs, or I am missing something obvious. It's such a f***around to get that cluster out when I have a speedo cable and not the digital speedo. I'm hoping to find an anser to my problem before I take it out again.
 
#4 ·
Light bulbs have far less circuit load area than a fuse, and can blow before the fuse if the problem is closer to the bulbs than the fuse, especially smaller bulbs such as these. You say that the dash light dimmer never worked. This suggests to me that there may have been a short in the circuit the whole time that manifested when it was disturbed. I have several ideas here, but perhaps changing the dash dimmer will fix this?

I'm wondering if it's possible the connector for the dash dimmer could be reversed, possibly touching 12V to what should be a ground. Also look for anywhere the feed wire to/from the dash dimmer might be pinched in the dash and shorting to ground (most likely cause). It's also very likely a wire that has bent for years now has an intermittent connection. Hope you find it in short order...
 
#5 ·
I am also putting inn a vote on the dimmer switch getting fixed before moving on to look at other things.
You know it is bad.

A faulty connection will cause voltage spikes that easily will blow bulbs.
Take for example my antique lamp with the bad switch. It eats light bulbs like it going out of style. Hit the switch it don't work. Hit it a couple time and it works but POP the bulb flashes and goes out. I gotta fix that thing when I get time.

After fixing the switch. There a plug in connector on the firewall the gauges plug into. Tweak the connections so they make good contact. Mine had no dash lights. Hit a bump and it did. Hit another and they were out again. That is what it was.
 
#6 ·
Looks like I have found the problem! I pulled the dash cluster out again, went inside into my office, put it on my desk and had a closer look.

Americans..
You never find these solutions on european or japanese cars. Why use something so easy-to-break on the back of an instrumentation cluster?

As you can see on the picture below I have circled one of the leads. This one is broken inside the plastic and should be the obvious reason why I'm not getting any power to my backlights. Question is, does anyone have an idea on how to fix this? I won't find any astros nearby and there must be a way to fix is somehow.
 

Attachments

#7 ·
Ouch... I don't think that's going to be an easy repair... I hate to say it but I think you're going to have to swap the whole instrument cluster from an older one. There are cluster restoration shops that might be able to fix it, but I would search eBay and Craigslist for possible donor candidates... you might also consider building your own with aftermarket gauges.

You might contact Drummernaut (site member)... They have an interesting thread on hacking the audio interface for the factory stereo to add an auxiliary input jack. Maybe they could provide a solution.
 
#8 ·
Skurt - found clusters for 92 and 93 models on eBay, are these the same as an 87? Pics don't indicate by comparison, but I've seen two pics for 87 that don't look the same. I am wondering if the back half of another year closer to yours could be used to replace the damaged printed circuit, using the front half of your existing unit?

http://www.ebay.com/sch/6000/i.html...s_Car_Truck_Parts_Accessories&_vxp=mtr&_rdc=1

I did have another thought, if you're comfortable doing it or know someone who can... simply solder a jumper wire to the actual terminal at each end of the affected printed circuit, which will effectively bypass the printed circuit... Looks sizeable enough that a basic 12-14 gauge wire would do. Might try crimping a spade terminal on the end of the wire and soldering the spade terminal to the connection, could make the repair hold up better? I would check to see if you have sufficient clearance in the dash for the jumper wire before doing this however.
 
#9 ·
You might try ^^^, but only when you are good enough to solder a piece of wire to a pane of glass.

Good luck, I doubt if you can break it any worse than it currently is.

Uncle Bob
 
#10 ·
Soldered the broken lead today, it was a quick and easy fix. Tested the connectivity and everything is good. Still, it did not solve my problem..

Will move on to testing headlight switch and dimmer switch. If they are the problem I will find a way to fix them both, I don't want to wait for weeks for new parts to arrive from the US. Everything is fixable with some willpower!

Edit:
I took the headlight switch and the dimmer switch apart and now I have backlight again!
 
#12 ·
Let's give a cheer:

Rah, rah, rah...

Sis, boom, bah...

Kick 'em in the ashcan...

Ha, ha, ha !

Super ! (Originally sounded like the switch was the parent cause to me, but what do I know ?)

Uncle Bob
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top