Function of Dim-Dip resistor

[vwdom1 0]

the missus's corrado failed the mot on parking lights not working (sidelights) he said they do work but the headlight and sidelights both come on when you click into the first position on the headlight switch.

 

they want the sidelights to come on at first position then headlights on the second.

 

it's not the switch as i've tried my mk2 one and it does the same.

 

i've got a feeling its always been like that :?

 

any ideas?

[Riley 0]

That's how they are supposed to work is it not? :confused4: I'm pretty sure that with the sidelights on, there should be a small voltage to the headlight bulb too. :confused4:

 

It should be fine as long as the full 12v/55w isn't lighting the headlight bulb until dipped beam is turned on.

 

Neil.

[Jon_vr6 1]

Has it got an uprated headlight loom ie is there connection from the battery to some relays in front of the battery??

[RW1 0]

The reason for the dim headlights when in the switch is on sidleights, is that your dim-dip circuit is still connected as per the factory. Absolutely nothing wrong with your Corrado. MoT man is a MoT failure :lol: :lol: Tell him to switch the ignition off with the sidelights selected. "Parking" lights are when in that condition ie. parked, and you will get sidelights only.

 

If you want to disconnect the dim/dip, go to the front left side of the engine bay behind the left headlight. There you will find a yellow in-line connector with yellow wiring either side. Pull apart and bag/stow. Now you will have sidelights only on the 1st position of the switch with the ignition on.

 

.

[vwdom1 0]

the headlights come fully on not dim, i get 12v down the sidelight and main beam wires it has got a uprated headlight loom and inpro angel eyes but i took the loom back to standard and it does the same.

 

i checked the wiring diagrams and it looks like its doing what its meant to, i also checked my mates corrado and its the same.

 

i don't really know corrado's as i am a mk2 man but i think theres nothing wrong with the car but wether i can convince the tester is anouther matter:(

[RW1 0]

I would still check that the dim-dip circuit in-line connector is isolated in the engine bay behind the left headlight. On side lights, it's applying some voltage at around 10 volts to the headlights when the sidelights only position is selected.

 

The shunt resistor is in a metal clip hung under the slam panel behind the left headlight. Follow the yellow wires back towards the battery and you should find the in-line connector.

 

LH Headlight Cavity a .jpg[/attachment:jozq7tx1]

This is the front left wing area with the headlight removed. The shunt resistor is the item in the green circle which is hanging loose but th eposition is roughly there. The red circle is the position of the yellow in-line connector. In this case it is disconnected and bagged/stowed.

 

If you are using the USA circuit diagrams, this circuit is not shown.

 

.

[vwdom1 0]

i'll try that tomorrow thanks peeps :notworthy:

[Supercharged 2]

If running an aftermarket loom you should disconnect the dim-dip resistor... you can do this as above or at the fusebox end - trace wires from the H/L switch loom.

[vwdom1 0]

yer i disconnected it and it worked and passed :) what is the point in that resistor?

[RW1 0]

It was introduced in the late 1980's (UK only c.1988?? ) to stop people driving around on sidelights only in urban areas. And not to dazzle other driver's in urban driving but make cars more visible at night. As above, the resistor is in series and drops the voltage across the dip beam lamp filament to about 10 volts so that it is working at a dimmer light output.

 

The voltage is still high enough though to activate headlight loom/relay mods, hence your problem.

 

The idea was dropped around about 1996 as it became silly with people driving on dim-dip on unlit roads. :cuckoo:

 

.

[Supercharged 2]

Some good info here so amended tread title.

[t700bes 1]

Wicked.. I'm removing mine too then!

 

I'm the "mates corrado" :)

[davidwort 0]

... the resistor is in series and drops the voltage across the dip beam lamp filament to about 10 volts so that it is working at a dimmer light output.

 

:lol: VW wiring doesn't get much above that voltage to the lights anyway, don't all corrado's run on dim-dip and dim-main beam all the time anyway!

[vwdom1 0]

Wicked.. I'm removing mine too then!

 

I'm the "mates corrado" :)

 

 

yes you are even though yours sounds like a cement mixer lol

[Rams 0]

This has helped me out, the painter must have connected mine back up. Maybe why my fuse burned out as it was too much voltage when the headlights were working on the side light position. I will double check tomorrow but think you have helped me sort it! Cheers

[tony_ack 0]

If you are running an upgraded loom you MUST unplug the dim-dip resistor, otherwise the dipped beam will come on with the side lights

 

Same goes for a MK2 running an upgraded loom

[Rams 0]

I've had a look just now but I assume I need to remove the headlight to get to the resitor?