Yup... the speedo part of the IP on my 92 has gone totally blank.

Lights light it up... so unless the back light has failed... it's a goner.

I suspect it's the back light or a loose connection. It blinked off last week then came back on. But so far today, no back on.

Tach and gauges all still work.

Hopefully it's just the light

I have both mine in both Vettes give up the ghost. I had one rebuilt and one I bought from a salvage yard. What pissed me off is the backlight on the rebuilt one went out about a year ago. I can see the readout lightly. I don't need to know what speed I'm going anyway and check it good for fuel every now and then. Takes me 2 to 3 hours to tear down and put back. You could do it in less time but I stretch it out. Work a little, cuss a little, sweat a little, proceed. I'm not in the mood to work that hard for a light bulb.

OK... it worked today... but at one point, lowercase "o" appeared to the left of the numbers!

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oh, and last night? hieroglyphics... it went wacko...

this morning? ok...

Loose connector?

It's either the display or the signal to it.

I'd start looking around, replace it, and then do a diagnostics on the old one.

Left of the speed readout where the average mpg goes I'm getting a SYS flash on my 91. It flashes 3 times about every 30 seconds. Anybody have a clue? Obviously I have to pull the codes. Not meaning to highjack but it is digital dash related. The 91 turns over but won't start. If I do get it to start (like once a week) and I get lucky enough to hear the fuel pump charge, it will run at idle for about 5 minutes then die. Then after that it will turn over and not start. I'm planning on having it towed out soon but just wondered if anybody has encountered this.


(not meaning to hijack usually means a hijack)

You're on the right track, pull codes! Short upper right corner to lower left corner on the ALDL connector.

Probably end up with a code 41 or ERR. If that happens, take the ECM from your 90, switch the memcal/chip and try again.

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I would check the condition of the battery/charging system. After that I would pull codes.

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Recently rebuilt alternator, brand new battery. Good point though.



Thanks for your response Axel.

Back to Andy's problem.

Andy, I'd pull it, check and clean the connections, reinstall and check before buttoning back up. Put it back together and give it a test ride. Tearing it down again is easier the second time around. Replace or rebuild as needed.

I have been in there before for a dead bulb... not an issue. If I go in, I am replacing all bulbs again, too!

A note, just saying... if you get a SYS flash AND the SES comes on, I can promise you that you have a C41 - loss of serial communications - meaning both UARTs have taken a shit.

In my case, if I did have a SYS code, I can't see them without the screen; I would need to hook up my laptop.

Just curious, can you make the codes display?

If so then it's in the speedometer circuit.
(yes Andy's problem)

Thanks Andy, pointed me in the right direction to look at.