Fault in the headlamp circuit.

[ChrisHC]

The first position on my light switch turns on the side lights as it should. But if I then turn on the ignition the dip beams come on dimly. The voltage measures 5 volts. If I disconnect the headlamps and re-measure, I get 12 volts. Does this indicate a problem with the K4 low beam relay or something else?

[BenHar]

Look up dim-dip on google.

Ben

[ChrisHC]

Well blow me, I had heard of dim-dip but had no idea it was fitted to some E30's. Searching on here, I see there was a discussion about it three years ago and a picture of the fitment, and there it is, lurking on my car.

Thanks very much, this board comes to my rescue once again, what an amazing resource it is!

[martauto]

Well blow me, I had heard of dim-dip but had no idea it was fitted to some E30's. Searching on here, I see there was a discussion about it three years ago and a picture of the fitment, and there it is, lurking on my car.

Thanks very much, this board comes to my rescue once again, what an amazing resource it is!

The 1980`s version of "daylight driving lights" I think.lol
I think they are soooooo cool.Have them on mine as well.

Mart.

[arrisbmw]

if you got 5volts measured with the load on , should be 12 v .
you have a voltage drop , somewhere in the circuit.
bad wires or faulty relays . bad earth
you can only get true voltage reading with the load on circuit

[ChrisHC]

if you got 5volts measured with the load on , should be 12 v .
you have a voltage drop , somewhere in the circuit.
bad wires or faulty relays . bad earth
you can only get true voltage reading with the load on circuit

That is what I originally thought, but it is in fact the dim-dip device brought into the circuit when the ignition is turned on, I have now unplugged both resistors and the effect has disappeared.

A mention in the Wiki would be useful.

[arrisbmw]

interesting thanks for sharing . where abouts are these resistors. could you post a photo when you get a minute .
thanks

[biffer]

Resistors are in a aluminium case bit smaller than a cig-packet bolted to the n/s inner-wing just behind the headlamp.
Their 2 cylindrical rubber connectors are in with the main loom on the n/s inner-wing in vicinity of ABS unit.

[martauto]

Resistors are in a aluminium case bit smaller than a cig-packet bolted to the n/s inner-wing just behind the headlamp.
Their 2 cylindrical rubber connectors are in with the main loom on the n/s inner-wing in vicinity of ABS unit.

There you are !!!

Never new that.lol

Mart.

[ChrisHC]

There is a picture in this earlier thread that helped me track them down:
http://www.e30zone.net/modules.php?name ... ght=dimdip

[Brianmoooore]

Resistors are switched in and out of circuit by two relays fitted behind the LH side of the glovebox, just below the blue relay for the windows for ignition on/door open.