SSkull

I've looked high and low, and can't find any references on this. The problem I'm having with my backlight on my gauges, from what I can tell, appears to be tied directly to my IPC. I'm hoping someone might have some insight into this.

The reason I believe it's tied to this is because the replacement cluster I put in had functioning backlights, so before installing I swapped the IPC board(to keep the correct odometer reading) and now it doesn't work. Meanwhile my original clusters backlighting also works now with the IPC board from the replacement one I bought. The only common part between swapping back and forth now is my original IPC circuit board. I'm hoping someone can give me an answer on this.

The issue I had with it was that the gauges would light up for maybe a week or more, then go completely dead on the backlighting for a few months, and then begin working again randomly. I'm hoping maybe it's as simple as needing to resolder a specific part since it's intermittent(bad connection?).

ncali

The dic wouldnt have any affect on the lights however there is a dimmer on the other side of the dash. I would check for a good clean ground behind the cluster and check each of the pins /sockets in each of the connectors for a tight fit and any corrosion

SSkull

It's not the dimmer, I've gone through the process of elimination and literally everything works fine on both of the gauge clusters, except, for whenever I connect my original IPC Circuit Board. Whichever cluster has that one in it, will not light up. I ended up swapping everything back and forth cause I had the time and just wanted to be positive.

Thanks for your help. I guess I'll just end up waiting the roughly 7k miles til I get to the mileage on the properly functioning IPC.

Bill Curlee

The IPC gage back lighting is NOT lighted with bulbs behind the gage faces!!.

There are TWO four inch long black light florescent bulbs on the far outboard corners of the cluster. They are powered by the big silver box on the back of the cluster. That silver box is a DC to AC converter and provides high voltage AC to the florescent lamps.

The gage faces are painted with a DAYGLO Paint and the gage faces glow under the black light florescent bulb light.

Make sure that converter box is properly connected and make sure that there are not any cold solder joints on the circuit board on the inside of the box.

Bill

SSkull

The converter box, the black light tubes, everything on both my original gauge cluster and the original one are all completely functional. I'm well aware that the backlighting on the C5's are achieved with the blacklight tubes.

I have swapped every single part between both clusters(the surround, IPC board, Power Supply, etc) between both clusters. Mixed and matches every possibility just for peace of mind, and the only time either one will ever not have a functioning backlight when installed, is when my original IPC board is installed which is why even though I've never seen it mentioned in the usual gauge cluster help threads, I can't see how anything else could be triggering this issue. Something on the board HAS to be triggering the intermittent backlight failure.

From soldering other PCM's in the past, I know just a small crack in the solder can cause issues, which is why I was hoping maybe someone can point out something that's connected to the backlighting on the board.

Hell, I don't know, it makes no sense to me, but maybe the only thing I can take a guess on is that on the circuit board, whatever the dimmer is connected to has lost a solid connection from the solder, and when disconnected it just doesn't know to send the signal to light up. But that's a very uneducated guess at best


I guess worst case, I'll pull the cluster back out when I have free time and just hit all of the points on the board and see if that does it.

MrPDJ

SSkul, I think I am experiencing the same issue as you. The IPC back lighting went out on my 98 a few weeks ago. I bought a used IPC thinking that I likely just needed to swap the power inverter on the back. Well, that did not fix the issue. As you experienced, the only way that I could get the back lights to illuminate on either cluster was to not use my origial IPC board.

One thing that I did notice after swapping the clusters was that the chime on my old cluster had stopped working (no sound). I don't know enough about the IPC board, but I wonder if the chime and back light issue are related to a common failure.

SSkull

No idea, it drove me nuts cause I initially figured I was going to need to get the black lights replaced like what the usual repair was. And I came across a cheap gauge cluster on eBay so I figured it would cost me some time and effort if it didn't work.

I swapped the power supply like you did at first, and that didn't do anything. Then when I swapped a Z cluster to my brothers base C5 cause he liked the look better, I swapped the DIC over to keep his mileage the same. After swapping his DIC over to my previous cluster, all of a sudden the cluster worked with out any issues on the lighting.

So then a few swaps later I realized whatever the issue was, was specific to the DIC causing the lighting issue. I lived for a few thousand more miles til my mileage lined up and swapped one last time.

Didn't have any issues with my speaker at any time, but if I remember right that was also easily swappable so you could do a plug and play deal and see if it's defective on one or the other.

The entire time I had tried to figure out my cluster backlighting issue I never found anyone havingy same root cause. All recommendations and old forum threads always had people replacing clusters completely, or pulling them to get the backlighting repaired. I don't remember once of anyone having it be something in the DIC causing the problem.