90 dash/climate/radio dim in daylight...H Code 74 in history

[Corvette95]

Need some help with this 90 I picked up. I have never owned a 90-93 , think I have or had every other year C4 except 84. The cluster and LCD are dim in daylight, as is the climate control and radio. It had a CCM code 74 in history, I cleared that and it didn't come back. I am using a FSM for a 92 as I don't have one for the 90 yet, only a preliminary which says the diagnostic tree "TBD". I think the lamps are very dim in daytime with lights off, but I suppose the 90 is just dimmer than my 95's? I have tried shining a flash light into the photocell, the lamps brighten up a little, much more with lamps on. I have turned the lamps on and covered the photocell with tape and verified the lamps dim. The dimmer switch does work and fluctuated the brightness. My lamp count is zero (Tech1a) with flashlight aimed at photocell and runs about 20-40 outside today which is a very cloudy day. I could pull out the radio and climate control and trouble shoot per the 92 manual, but I "guess" it will check out. Is this a known problem before I start taking it apart? I was thinking photocell but it seems it is working with an accurate count? I could put a resistor in the photocell but at 0 lamp count it wouldn't get any brighter? It is brightest with lamps on with flashlight aimed at photocell than any other circumstances. Any idea's?

[PhillipsLT5]

From Dynomite Solutions
74 LED display dimming output circuit open or shorted to ground

[Corvette95]

From Dynomite Solutions
74 LED display dimming output circuit open or shorted to ground

I have searched for a specific thread on this but didn't find anything. I am more curious to know if anyone else has a dim 90 dash in daylight as the code 74 has not reoccurred.

[Ccmano]

Here’s the page from a 90’ Manual. That’s a history code which means the problem is intermittent. Follow the tree and let us know what you come up with particularly the diagnostic aids section.
H
:cheers:

https://farm66.staticflickr.com/65535/49534985982_6f40b4e279_c.jpg (https://flic.kr/p/2iteKys)

[Ccmano]

I should add, a dim (washed out) LCD is common by itself. They can and do go bad. But it does sound like you may have a dimmer switch and or photo cell issue. I had a good LCD but a dim cluster. I ended up replacing the DIC with the photo cell and replacing the cluster with a rebuilt unit. Check out www.Batee.com
H
:cheers:

[Corvette95]

Thanks for the manual photo, I have emailed Batee and waiting for reply.


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