Ignition switch questions 00 beetle

[KROUT]

I have a customer that came in about 6 weeks ago with a bad ignition switch. The car had no head lights, horn, wipers, and turn signals. So I get the wiring diagram out and found that the red wire with black stipe at the ignition switch has no power coming out of it. No problem replace the ignition switch and everything worked great. I should also add the car had 2 bad fans and a blower swithc on the dash. So after 2 fans one ingniton switch and ac control it went out the door.

Today it comes back with the no lights,horn and wipers again. The switch is bad again,but this time the red wire on the switch harness has clearly gotten hot and partially melted the coating where it attaches to the plug. The wire still has good power on it. I plug a new switch in and everything works again. I can not find any reason for the burnt wire other than a shorted switch. All grounds are good and relays seem to be working properly.

I am 99% sure that the switch shorted out some how and cause the damage to the wire. Just wondering if anybody has seen this before.

The wiring diagram shows that that red wire is fed power from the load reduction relay(100) It apears to be working great. I hate to send this car out the door only to have it happen again and do wiring harness damage.

Thanks for any help.

 

[Antsrcool]

Was that switch right from VW or was it an off brand?

 

[KROUT]

No is from the dealer. I dont use cheap parts on my customers cars. I stay with oem unless other wise requested.

 

[JetPuf]

This is a problem with some beetles, mine has done this. I isolated it to the factory fogs. they are not relay-isolated, so when you have all the lights on, and kick on the fogs, you're drawing a TON of amperage across that switch.

 

[KROUT]

Thankyou that is possibly the problem. With the fog lights on the wires get warm. But not any other time do they get warm.

Wht do you do to correct it. Wire the fogs threw a relay?

 

[JetPuf]

yup, wiring them through a relay was my solution. I think VW simply spec'd a wire that was just a little small for such a current draw.

 

[KROUT]

If your ever in Jax fl you have a free beer coming. You just saved me and my customer some diagnostic time.

Acording to my wiring diagram the fogs do ruin threw a relay. Maybe its just bad.

Thank you

 

[JetPuf]

I dont have the wiring in front of me... I found nothing wrong with my relay for the foglights, yet I still needed to isolate the circuit.

 

[BugBug]

Check the connector prong on the wire side and make sure it makes solid contact with the male prong on the ignition switch. If the spade connector does not make solid contact, even a low amperage draw over the connection will heat up/arc and possibly melting the internal parts of the ingnition switch, the wire or both. Safest bet would be to pull the questionable wire out of the connector assembly and put a new end on it.
Post back with results. Hope this helps.

 

[JetPuf]

Good advice. However when I replaced my switch, I had to splice in new wires, they were fried! I'll see if I have some pictures when I get home for the curious.

 

[KROUT]

It making solid contact. But as soon as the fog lights are turned on the wires get hot. I am going to just rewire the light switch threw a relay so it pulls power form the battery and not the ignition switch. I am going to use the ignition switch wire to trigger the relay. So the switch will work just as it does now without the major power draw off the ignition switch.

I am amazed at the size of the wire they use from the headlight switch to power the fog light relay. It apears to be like 18gauge wire very small. I can see using a small wire to trigger the relay but not to power it.

 

[KROUT]

Well the relay did the trick no more hot wires. I still doesn't make sense to me why the load one circut that much. The fogs have there own relay put it pulls power for the relay from the headlight switch(very small wire). I now have the fogs lights on one relay and the head light switch on another it is working as it should now.

 

[JetPuf]

I think the relay is there simply as a cutout for when the high beam lights are on.

 

[jollyGreenGiant]

Good thread. Silly VW...

 

[KROUT]

Sent the car out the door today working fine. The only diffence is an extra relay and fuse.lol