Unkown & Unused "Ignition" Ballast Resistor in Engine Bay
Discussion
Hi all,
on my 1981 280i FHC +2 there's an ignition ballast resistor next in the engine compartment, on the right-hand side of the radiator. It's like this one: TVR Parts 025M 165A Ballast Resistor
It appears to be somewhat useless as I daily drove with it - by accident - disconnected and no functionality missing.
Does anyone have any info on this resistor?
Additional Tech Info:
- It is not the ignition ballast resistor (which is the stock, coiled, thick blue wire next to the K-Jetronic fuel distributor).
- Accessories tested with resistor disconnected: Blower works on 2 speeds, all lights and motors work, radio works
- The resistor has two leads: one connected to ground, one which has ~5Ohm to driving light & beam, ~22Ohm to ignition-on-dependent accessories
- When enabling driving light 55mA are drawn via the resistor (but again, they work fine without)
- I neither have a fitting electrical wiring diagram nor can I find it on the next best matching one
- Its two connections seem to go alongside the main loom through the fender into the cabin
- I couldn't test the functionality of the heated rear window - but figured the resistors connecting cables are pretty small for such a usage
Thanks and Greetings
Theo
on my 1981 280i FHC +2 there's an ignition ballast resistor next in the engine compartment, on the right-hand side of the radiator. It's like this one: TVR Parts 025M 165A Ballast Resistor
It appears to be somewhat useless as I daily drove with it - by accident - disconnected and no functionality missing.
Does anyone have any info on this resistor?
Additional Tech Info:
- It is not the ignition ballast resistor (which is the stock, coiled, thick blue wire next to the K-Jetronic fuel distributor).
- Accessories tested with resistor disconnected: Blower works on 2 speeds, all lights and motors work, radio works
- The resistor has two leads: one connected to ground, one which has ~5Ohm to driving light & beam, ~22Ohm to ignition-on-dependent accessories
- When enabling driving light 55mA are drawn via the resistor (but again, they work fine without)
- I neither have a fitting electrical wiring diagram nor can I find it on the next best matching one
- Its two connections seem to go alongside the main loom through the fender into the cabin
- I couldn't test the functionality of the heated rear window - but figured the resistors connecting cables are pretty small for such a usage
Thanks and Greetings
Theo
Same type of ceramic ballast resitor that is fitted to Triumph Stags definitely for the ignition circuit in that application. Allows full 12v to the coil for starting then reduces it to 6v for running.
Maybe a PO has used it instead of the resistive wire in the past? Can't think of any other use for it.
Maybe a PO has used it instead of the resistive wire in the past? Can't think of any other use for it.
Hi all,
thanks for your replies!
phillpot had the nose for the issue, it's the dimming of the instrumentation illumination.
I guess the resistor went bad before I got the car and thus never knew of the functionality's existence
The resistor appears on the wiring diagram, too. It's positioned as part of/next to the panel illumination switch.
Greets, Theo
thanks for your replies!
phillpot had the nose for the issue, it's the dimming of the instrumentation illumination.
I guess the resistor went bad before I got the car and thus never knew of the functionality's existence
The resistor appears on the wiring diagram, too. It's positioned as part of/next to the panel illumination switch.
Greets, Theo
Edited by mrlaberlaber on Tuesday 6th April 22:00
Gassing Station | Wedges | Top of Page | What's New | My Stuff