Halogen headlights

[Alec]

Hello Mike,

to elaborate slightly, the resistors are in series in the brake and indicator circuits and reduce the voltage. Obviously they were sized to do as you say with the indicators. Simple normally made contacts of the relay short out the resistors when the lights are off.

Alec

[CAR]

For those interested, the Night Dimming Relay was fitted to 'early' Mk2 cars and on saloons is fitted behind the LH boot side trim and is a blue thing about 3" cube- ish. The simplest way to 'remove' it is to disconnect it's black ground wire. The relay will then not operate and the lights will stay in full power mode. I have it disconnected in both the 2000 and PI.
Cheers,
Mike.

Were they fitted to the estates, or was it decided that the rear lights were dim enough already?
I have always thought as the rear lights on our cars are so low down in comparison to modern cars, and hooded slightly, that a high level brake light would be a good addition (I haven't fitted it to either car yet!). Also most people seem to drive so close to each other and look for that middle brakelight. Yet another example of falling driving standards as a whole.

I assume that my pi being fairly early has had the relay bypassed. It's eay to check by yourself if you are concerned, just reverse up to a wall/garage door/fence etc. and apply your brakes. Whilst holding the brake pedal down, switch on your lights and see if they dim.


Colin.

[sorbs]

I thought all mk2s had the night dimming relay? I'm not sure. I'm pretty certain that my '74 estate did.

If I'm queueing for long periods of time in the 2000 or am dazzling the driver behind with my brake lights when driving a modern automatic then I'll put it into P or N and apply the handbrake. In normal situations I just hold them on the brake - one of the nice things about an auto is the ability to creep along slowly and smoothly in traffic just by modulating pressure on the brake pedal.

I owned a modern Jaguar a few years ago and put it into 'P' one day whilst waiting at some traffic lights. The lights changed but the selector had locked in P. The car was completely immobilised and couldn't even be pushed out of the way!! Eventually, a frantic sequence of locking / unlocking / getting out / re-starting the car eventually re-set whichever computer had caused the problem and I was able to select a gear again. I wasn't too impressed when Jaguar told me that it was a known fault for which they hadn't found a cure. I just held it on the brake from then on.

I think the subject of poor driving standards is worthy of a thread of its own!

[Mike Stevens]

to elaborate slightly, the resistors are in series in the brake and indicator circuits and reduce the voltage. Obviously they were sized to do as you say with the indicators. Simple normally made contacts of the relay short out the resistors when the lights are off

Well, yes. As well as those obviously in series to reduce the power to the bulbs, there are also some in parallel with the indicators to keep the total power drawn by them constant, dimming relay on or not. If these were not fitted the indicator speed would change, side lights on and off. I think I'll go and find a relay and dismantle it. There's nothing like reverse engineering!

I've only ever seen these units fitted to saloons, but both estates I've had have been 'S' varieties and I don't think the dimming relay was fitted to either saloon or estate that late. I will have to go and look up in the various books and see!

Another way to see if it is working is to switch on the lights. The relay will 'click' from the LH side of the boot if still wired. Of course, some silly 'person' may have left the relay coil in circuit, but re-wired the contacts, so this method won't work then!

Cheers,
Mike.

[Alec]

Hello Mike,

just had a quick look at my manual (It does say saloon only), and there is a fourth resistor as you say. Quite clever as there seems the series resistor was selected to get the right voltage for a desired light output but this current was insufficient to keep the frequency correct so some current is shunted to the the lamps on the other side (i.e the opposite flasher circuit. It does say that this voltage is insufficient to light the lamps). This is done with the right flasher relay contacts being a change over rather than a N\C on the other two circuits. This resistor is connected from the N\O contact to the input of the left hand flasher.

Alec

[wild bill]

Getting back to the halogen headlights,I will endeavor to stick to the standard sealed beams as long as I possibly can for the sake of originality.Having said that,I'm really tempted to have a set of side,stop & tail L.E.D. lamps just to improve lumens quality and save on power draw,seeing as I still have the dynamo.
I have just ordered a pair of iridium angel eyes for the mini,as they will compliment the L.E.D. halo rear lights.Don't have to worry about originality there,then!

[jimlodder]

For my newly acquired 2.5 PI Estate I have purchased a halogen kit from Rimmers (in their sale) that came with a relay. However, the instructions supplied don't make a lot of sense to me - anyone able to advise how to wire in the relay please? It's got 4 terminals C1 C2 W1 W2
Thanks

[Alan Chatterton]

Relays are usually marked up pins number 85, 86, 30 and 87.

85 goes to earth
86 goes to the switching circuit
30 is the main power feed
87 is the item you are trying to use(lights, horn etc)

W1 = 85
W2 = 86
C1 = 30
C2 = 87

So, connect W1 to earth, W2 to the original wiring feed for the lights (switching), C1 to power (battery or starter motor feed) and C2 goes to the lights.

Hope this helps.

[murcod]

I don't know if this has been mentioned, but older BMW 3 series Hella headlights will bolt in with only a few mods to the BMW lights. They've also got a lot better rear water/dust seal than the aftermarket halogens (also Hella) that were already fitted to mine.