90 Town Car - Digital Dash is dim

Really have two issues you may be able to help with.
1. The digital dash is working fine except that it is very dim. Any thoughts?

2. The A/C is acting strange. When I step on it, it switches to defrost. Sounds like a vacuum problem! The dealer suggested the control head in the dash but I changed it with the same results. Any ideas as to tracking the problem down?

Thanks for any help in advance.

I am not familiar with your model year, but ask:

1) Is it the whole dash that is dim or just part of it> like the speedometer? If just a fraction is dim, then it is likely a bulb for that location. That is how our '88 Tbird is.

2) AC. My comment is---an air leak in the control mechanism hose. My wisdom ends there. Others may help or you could check Lincolnsonline site as well.

1. The elcetronic display is vacuum florescent and the whole cluster has to be replaced. It can and does wear out over time.