Heater control issues - E38

[Diller]

Hey guys,

I've been noticing a strange thing on my 740il. When I run my A/C, the lighting on my heater control dims and gets brighter. This goes on as long as I run the A/C. If I switch to any other mode, the lighting brightness stays the same.

Am I possibly looking at a failing heater controller?

Diller

'98 E38

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[straight6pwr]

voltage issue?  the computers tend to just stop working versus act funny.

 

i'm not familiar with e38s, but you should find an ETM wiring diagrams and trace where that bulb is powered from.

is it one of the lights that will dim with the dash board dimmer switch? do any other lights do the dimming thing?

[CMart]

I think these are the same as the E39s.

 

I have some spares you could use to test if you'd like.

[Diller]

I should be more specific. The LED readout for the dual zone climate control is what is doing this, not the physical buttons.

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[CMart]

I believe those are liquid crystal not LED. They are known to go bad over time.