Jump to content


Photo
- - - - -

dim dip relay...


  • Please log in to reply
7 replies to this topic

#1 screech

screech

    Up Into Fourth

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 3,136 posts
  • Location: West Sussex
  • Local Club: Bognor rock ya mini & WSMOC

Posted 19 December 2005 - 04:45 PM

got my loom today, really pleased in good condition and fully labeled! Its got a 'dim dip relay' what is this, im sure mine didn't have one when i ripped it out!
also it has a radio plug wiried into the loom 'as standard' does anyone know if it is perm live or switched with the ign, saves me wiring it in! :lol:

#2 dklawson

dklawson

    Moved Into The Garage

  • TMF+ Member
  • PipPipPipPipPipPipPipPipPipPipPip
  • 10,923 posts
  • Name: Doug
  • Location: Durham, NC - USA
  • Local Club: none

Posted 19 December 2005 - 05:12 PM

I'm surprised that the manufacturer of the harness added things that weren't stock for your application.

The dim/dip relay would be for your headlights. It's common on older cars to add these to the wiring, especially when upgrading to Halogen lamps. The use of the relay protects your dash wiring and helps extend the life of the lighting switches.

#3 screech

screech

    Up Into Fourth

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 3,136 posts
  • Location: West Sussex
  • Local Club: Bognor rock ya mini & WSMOC

Posted 19 December 2005 - 06:01 PM

mines a 1988 jet black. this is the loom...
clicky

#4 Turbo Nick

Turbo Nick

    Up Into Fourth

  • Members
  • PipPipPipPipPipPipPipPipPip
  • 2,913 posts
  • Local Club: Turbominis.co.uk

Posted 19 December 2005 - 06:32 PM

when you put your sidelights on the dim-dip thing also puts a little power to your headlights so your sidelights appear brighter. I had to disable it when i fitted the angel eyes as it ruined the look of em.

#5 Dan

Dan

    On Sabbatical

  • TMF+ Member
  • PipPipPipPipPipPipPipPipPipPipPip
  • 21,354 posts

Posted 19 December 2005 - 11:29 PM

Sorry DK, the dim-dip system isn't a headlamp relay in the normal sense.

It doesn't protect the wiring or the switches from the main beam load. It's a system required by the Construction and Use (Motor Vehicles) Regulations for all new cars first used after 1988 in the U.K.

Its purpose is to prevent you driving your car on sidelights only by bringing the dipped beam on to roughly half intensity if the side lights and ignition are on at the same time. It uses a large resistor (fitted behind the radiator) in series with a secondary supply to the dipped beam filaments which is switched by the large relay pack under the dash when the ignition and sidelight circuits are on but the headlamps are not in order to reduce the voltage accross them.

It's roughly equivalent to the day running lamp circuit required in Scandinavian countries and used for similar reasons, it's very easy here in winter to not realise just how dark it is and how early it gets dark on these short days.

If your car is pre '88 then it's not required. I recently wrote a reply on here to someone asking how to simply disable it. I'm sure you don't want to go chopping about your new loom so search for threads about Angel eyes and dim-dip and you'll find what I wrote. I can't remember which terminals in the relay you need to link together to isolate it at the moment so you'll be better off checking back with the previous post.

#6 chairchild

chairchild

    Super Mini Mad

  • Members
  • PipPipPipPipPipPip
  • 606 posts

Posted 20 December 2005 - 12:18 AM

Dan - I love you



I thought my sidelights went dimmer when I turned my engine off because of a dodgy electrical problem! (I've had plenty of them). And it was a fairly substantial drop in brightness - what you've said has made my life a lot easier when I come round to fixing the mini - since they're not actually broken!!! :lol:

#7 Beaver

Beaver

    Starting My Mini Up

  • Noobies
  • Pip
  • 1 posts

Posted 21 December 2005 - 10:54 PM

Dan,
I have been trying to get a set of spots working correctly.
Fitted 2 spots and 2 driving lights, all running off one relay... activated by highbeam switch on steering column (blue/white wire)
They come on when highbeams are switched on, but do not turn off.

After reading your piece above, I think it may be the fact that the dimdip unit holds voltage at half power. Using multimeter I found that voltage on highbeam switch remains at 5.8Volts, until swithing all lights off.

Is there some way to overcome this problem??

Many Thanks

#8 Dan

Dan

    On Sabbatical

  • TMF+ Member
  • PipPipPipPipPipPipPipPipPipPipPip
  • 21,354 posts

Posted 22 December 2005 - 01:15 AM

The dim dip system has no connection into the high beam circuit so that can't be causing it. Unless someone has played with the wiring in the past and messed it all up. When it's setup properly the half voltage side is only connected between the relay and the dipped beam filaments and doesn't go near the lighting switches.

It sounds to me like your relay could be self exciting. Did you use the type of relay with a built in diode? If it does have one then the diagram on the side of it will have a diode symbol (an arrow) in parallel with the coil. This kind of latching behaviour is what you normally see when relays do this.

The diode is a good thing, and stops the self exciting stuff.

by the way, spot lights and driving lights are the same thing.

Edited by Dan, 22 December 2005 - 01:16 AM.





1 user(s) are reading this topic

0 members, 1 guests, 0 anonymous users