w126 late Gen 2 potentiometer/rheostat
 

Guys,

When getting ready to purchase a replacement, several sites have before chassis 491584 and a different part for chassis 491585 and after, starting in '89. Here's my conundrum: my car is '87 but the donor engine/transmission (and donor EZL and ECU) that is going in is from a '90, well after the updated part. Currently I'm using the '87 instrument cluster. Is the updated part particular to the cluster, or the electrical modules? When I put the donor '90 cluster in (which has wonderful bright orange needles and orange-yellow script) in the future after final interior refurb, will I need the updated part then?

Thanks,
Drew

D:

There are two subject areas in your post:
1) engine controls; the EZL & ECU
2) the "cluster" - Instruments?

If #1 the potentiometer is in the CIS airflow meter.
If #2 the potentiometer is in the instruments.

Care to clarify?

Frank, it's the dimmer on the back of the instrument cluster. I just wonder if anything from the donor engine/electrical modules have any bearing on the cluster. I wouldn't want to blow out a new $70-$120 part if I mistakenly put the wrong one in.

The dimmer is independent.

So if I'm understanding correctly in this situation, should I order a pre-'90 potentiometer/rheostat dimmer for the '87 cluster still in the car, and when I put the nicer looking '90 cluster in, install the updated potentiometer/rheostat dimmer?

Give a thought to comparing the two instrument sets, and their dimmers, side by side. The dimmers may possibly be interchangeable, at least physically. If so, measure the resistance of the dimmer coils. Does either work, or neither? Cleaning the coil & wiper can be effective.

Will do, thank you very much Frank.