ip cluster completely black

[fjr48]

Hello,

I'm working on my first 1989 car and the cluster doesn't light up at all. The touch screen works fine. I checked for 12 volts at the cluster connectors (cluster removed). I do have 12v on the ign terminal on the left side and 12v on both cps terms on the right side.

My question is, is the failure mode for the 89 cluster to be totally black at key up ? I get no check engine light, brake light etc. The entire cluster is as it would be laying on the bench. Absolutely nothing lite up.

I would appreciate any help, thank you

[Guest Recian]

If i recall correctly there's a communication between it and the CRT. If the cluster is taken from the loop it'll throw a code of some kind that can be accessed through the CRT. If it' not lit up and the code isnt there then it's communicating just not lighting up. You did check the basics, fuses and grounds right? I have a spare IPC and CRT laying around for these things to swap just to check.

[padgett]

Pull it first (only about 4 screws) and R&R making sure the connector is in securely in the dash cavity. The connector is captive in the dash and mates when you put te IPC in. Not a great idea but seems to work mostly.

[fjr48]

The fuses checked out OK.. The connectors seem to have a lot of side to side movement in the ip housing, I guess to assure alignment with the cluster connections. Both connectors are retained from being allowed to move back as the cluster is installed.

I found more info in the service manual that provides complete pin outs for both cluster connectors. I will go thru those tomorrow. The local junk yard has a 88 or 89 Riv with the dash all still there, so I will get all the cluster, cps, touch screen etc. so I will have extras also. I'm just hoping it didn't throw some monster spike that took out the first cluster. If it did, I sure hope it doesn't do it again !!

Thank you very much for the help !

[fjr48]

I wanted to close the loop on this cluster issue. The system continued to check ok so I went to the junk yard and got a cluster. Plugged it in, everything works. It just seemed strange to me that on the other cluster I didn't get any indicator lights at all, as well as the display being black. With the new cluster all indicators are working and the display is too.

Thank you,

[Guest Recian]

good thing it's resolved. When you said CRT had no codes thats why i was thinking the IPC was powering up but just the display circuit had failed. If i remember right there's a display circuit in the IPC that somebody on this site has learned how to rebuild. Could be something else or maybe it's the 90-91 IPCs. I have a bad memory so i could be mistaken.

I keep a spare set of modules for my 89. For this very reason. Ive learned over the years computers can do whatever they want. They dont always have to make sense and can be difficult to diagnose. The reatta uses 20 year old computer technology. That being said theyre more indistructable but more accident prone than modern modules. If you intend to keep your reatta or buy others try to keep a set of modules around for them. It seems these cars are more prone to wiring problems or loose connections but modules are never out of the question being as old as they are.

Edited September 2, 2011 by Recian (see edit history)

[NCReatta]

'88 and '89 clusters very rarely go bad.

I've seen some that have had terrible abuse. Some in very high milage cars, some in cars that had a lot of moisture in them, cars that were kept in the sun 24/7, etc. and they all kept ticking right along.

It would be interesting for someone who knows what they're doing to tear yours apart and see what went wrong.

[Guest Recian]

like i said my memory is pretty bad but i know someone on here mentioned taking a CRT or a IPC apart and fixing something with the display in a thread a few months back

[padgett]

The 88-89 IPC can fail just does not happen often.

[NCReatta]

like i said my memory is pretty bad but i know someone on here mentioned taking a CRT or a IPC apart and fixing something with the display in a thread a few months back

Yeah, KDirk has developed a reliable fix for the 90 and 91 clusters. He would be able to figure out what went wrong in this one..

[Guest Mc_Reatta]

88 and 89 IPCs do go bad but not as frequently as the 90/91s.

They can fail in stages also. I had one that lost most of the idiot lights yet would still show the data displays fine.

I expect the failure modes to be very similar to what KDirk found in the 90s.

Cracked solder joints in the ones that are intermittent, and bad power supply parts in the ones that go black. Electrolytic capacitors are always suspect.

Definitely repairable.

[KDirk]

May as well chime in here. I think the big difference between the 88/89 and 90/91 clusters is that the former used almost all through-hole mount electronic components (pins are soldered through small holes in the circuit board). the 90/91 design was more heavily reliant on surface mount (SMT) parts, which solder to small "pads" on the surface of the circuit boards rather than having pins that go completely through.

The reason the older through hold design is more reliable is simple: there is more surface area on each pin of a component to be soldered, and more solder to hold the pins in place. This makes them less susceptible to hairline fractures in the solder joints that can cause intermittent problems or outright failure as we are now seeing frequently with the 90/91 IPC's.

All that said, I think that we will start seeing 88/89 clusters fail at a greater rate in the next few years, as they start to suffer the effects of constant vibration and cold/hot cycles that occur in the car. It is just that they will last longer than the 90/91 design based on a more reliable manufacturing process insofar as the circuit board layouts.

Anyway, I have not looked in detail at an 88/89 cluster yet, as there has been no need for me to undertake the research needed to develop a repair process for these. This due mostly to the much lower failure rate of the early model clusters. When there is sufficient demand (or when I have some free time - yeah, that's a good laugh right there) I will look at the 88/89 IPC.

One other thing regarding clusters - and all electronic modules - is the aging of certain components. Most notable are electrolytic capacitors. These employ a liquid paste electrolyte contained in an aluminum can, unlike ceramic, mylar and other film type capacitors that virtually never go bad. The electrolyte paste can and does dry up, causing the loss of capacitance. Once this happens, the part is junk, and usually induces a failure of the circuit which it is part of.

I have also seen carbon composition resistors (especially low value ones, under 10 ohms) drift wildly of their specified value after many years. This is another problem that may start affecting the electronics in these cars in the longer term. I try not to worry too much about this, but I imagine someday I will be rebuilding nearly every module in the car if I want to keep it running right. The thought of that much soldering and rework makes me cringe, so I try to ignore it for now.

One thing to be thankful for is that GM of the late 80's over-engineered the electronics to nearly mil-spec standards. This has contributed to their long lifespan (20+ years) to where we are just now seeing greater rates of failure. Not bad at all considering what these modules are exposed to in terms of temperature extremes and road vibration.

If enough people want me to do a post-mortem on a failed 88/89 cluster, I will try to make time for it, as I always welcome a learning experience. I just don't think we're at the point of critical need yet.

KDirk