Check control lights

[cschollum]

Here's a check control problem I've never seen posted before:

The LCD panel in the instrument panel on the '90 535iM (for sale) has a problem. The display sometimes illuminates faintly, other times not at all. The characters on the display are active and can be seen (fasten belts, light on? etc) if I shine a torch on the display. The lamps themselves check out OK.

What module is responsible for activating the two CC light bulbs?

The SI display lights up OK on startup - it is part of the same LCD as the CC, odometer and auto trans indicator's functions. I'll double check the diagnostic mode later but I think it is dim then as well.

As the car is for sale, I don't want to spend $$ fixing but would prefer it worked as there's less for prospective buyers to gripe/negotiate.

Same problem as always isnt it? bulbs need replacing?

if the bulbs are ok and youre sure(would seem odd) as this is always the problem, perhaps they arent seated properly or maybe a faulty instrument cluster as its that that controls them, presuming that the speedo is illuminated ok - the actual signal comes from the dimmer switch located on your dashboard

as a side note, the lcd section atually plugs into the cluster, if you take it apart its a seperate module, and the bulbs are seated in a ribbon plastic material and if the bulbs have been replaced quite a few times then the ribbon wears away rendering the bulbs inoperative