1993 K75S - COOLANT OVER TEMPERATURE WARNING LIGHT

[GasStation]

I have a 93 K75S and when I turn on my ignition key, the coolant overheat warning lamp in the instrument panel does not light up.

I have a simple question for this forum:Can anyone confirm that their coolant overheat warning lamp in the instrument panel lights up with the ignition switched on?

The Haynes manual clearly states that the oil pressure warning light lights up with the ignition switch on but does not mention anything about the coolant warning bulb.

I may have a coolant overheat warning lamp burnt bulb, wiring issue, or faulty relay switch but first I wanted to solicit your help.

[Inge K.]

The coolant warning light does not light up when you switch on the ignition.

Inge K.

[frankenduck]

Here:

[GasStation]

Thanks guys, very very much appreciated.

Is there a reason that you may know of why BMW did not wire the coolant over temperature warning light like the oil pressure warning light so a bulb check can be done before engine startup?

I read that the only way of checking the serviceability of the bulb is by removing the tank and doing a grounding check A3 to earthing point 31 on the temperature switch in the relay box. Does this make sense 'cause it is a lot of trouble to check a bulb? :loopy:

[frankenduck]

Is there a reason that you may know of why BMW did not wire the coolant over temperature warning light like the oil pressure warning light so a bulb check can be done before engine startup?

I read that the only way of checking the serviceability of the bulb is by removing the tank and doing a grounding check A3 to earthing point 31 on the temperature switch in the relay box. Does this make sense 'cause it is a lot of trouble to check a bulb? :loopy:

Probably a design or cost issue.   It's really not all THAT important as, just like in a car, the radiator cap will blow before engine damage is done.

The other way would be to pull the back of the instrument cluster off and test the bulb.

Since it never goes on the chances are very high that it's as good as a brand new bulb.