Smoking Headlight Switch

Hi All,

I was recently driving down the motorway when I lost all dashboard lights and instruments.  I initially thought i might be linked to the headlight switch, so ordered a new one, but after a bit of investigation I traced it to the earth strap from the corner of the rocker cover.

I replaced this, and this seemed to fix the problem.  While I was at it, I decided to put the new Headlight switch in too (as the rheostat for the instrument dimming was a bit iffy on the old one).

Next time I drove with the headlights on, I started smelling burnout, followed by smoke coming from the vicinity of the Headlight switch.  I stopped and put the old switch back in.  I don't have any smoking anymore, but if I turn the headlights on, I still get a feint smell of burnout, and the switch is quite warm.

Linked to this (I think), whenever I turn the headlights on, the indicated outside air temp and oil temp on the MFA go up by 4 to 6 degrees.

I am thinking that this is an earthing problem, but after checking the current to the switch and rheostat, can't find a problem.  I am now too scared to drive when I might need headlights, as the last thing I want is a wiring loom fire!

Any help would be greatly appreciated.

Thanks in advance

(1983 GTi - 2 owners, and just as it left the factory)

Relay the headlights so all the power is not going through the light switch.
Lots of kits for relaying headlights and info on here and web.

Sorry can't be much help with electrics as not my thing.  

Check the gray/blue wire out of the back of the switch it is the cluster light/console lights lead.  It can get nicked and burn things.


Relaying the headlights to off load high current on the switch is a good thing and you will increase the efficiency of your lights by 2Volts usually.

 

Thanks,

I'll have another look at the grey/blue wire from the dimmer, but I think I already checked this.

Any ideas why the MFA readings drop when the headlights are switched on?

Thanks again,

Neil

LCYCowboy said

Thanks,

I'll have another look at the grey/blue wire from the dimmer, but I think I already checked this.

Any ideas why the MFA readings drop when the headlights are switched on?

Thanks again.

Neil

Bad Grounds.
Bad Grounds as I call them or Earths as y'all call them are the second most bane of the GOLF/Rabbit/Cabriolet/most VW's.

There is a Star connector on the firewall cabin side that can get loose, rusty and tarnished connections.

There is the Valve cover to the Coil Bracket ground that can get crud/tarnish/missing.

You have the Battery to Frame and Frame to engine/tranny.

Cleaning, and replacing grounds only assists you with better electrics all round.

There is the Ground connector on the instrument cluster pin 2 (brown).  I have found the following things to greatly improve the workings of the cluster.

1. Remove the Shroud on the main connector, carefully lift the mylar off the tongue.  

On the plastic tongue (pad side of the mylar) place one piece of Electrical tape on the tongue.  Replace the mylar, and the shroud, This will tighten up the probably slightly bowed connection firming up the ground, (pin2) and the 12V in….

2. Take a Scotch-lock Wire splice and Splice a 10 inch pigtail wire to the brown (earth) on the connector side about 2 inches back or so from the connector.



Drill a Pilot hole between the "X" brace of the cluster.
Clean the pilot hole to bare metal.

Place a Ring connector on the Pigtail wire and make sure it is a good crimp.

Using a self drilling, or Sheet metal screw, screw the ring connector to the frame at the pilot hole.



VW imho, didn't do a through and through check of Grounds, and piled too many at the same place, instead of "Balancing" them.  

I have heard of main ground issues that well when you hit the starter that the starter gets ground via one of the following..

ECU, Sensors, Speedometer Cable, Clutch Cable, and it has melted or fried all the above….

Try putting 40Amps of Current through the Instrument cluster or Speedo-Cable…..


My 2 scents…

the gti clusters earth to the side of the head so make sure this wire is good, its the brown/white. if addign the braided earth to the rocker cover helped this suggests to me the main engien earth to the top of the gearboxisnt very good so look at that next