The P30 light switch in our gas Barths is the same as used in Chevy trucks and cars for many years. It is not up to the task. Neither is the wiring to and from it. You can verify this by leaving your lights on for a while and feeling the wires with your hand. they will be warm. Warm wires indicate some electricity is being converted to heat instead of light.

You can check your headlight voltage by reading the voltage at your headlight terminal. Just pull the connector back enough to expose the brass. Then read your battery voltage at the battery. The difference is what you lost. For fun, check the voltage at your toad tail lights. Toad tail lights are important as some of us drive a little slower with a toad.

A heavier switch and wires would be nice, but difficult. A better way is to install a relay. I like the Bosch black relay. Any good auto store or auto radio or alarm shop sells them. Avoid third world copies.

Here is a good web site on the Bosch relay:

http://www.6066gmcguy.org/wire-tips.htm

One quibble: I disagree with their usage of a bleeder resistor instead of a clamping diode to deal with counter EMF.

An ideal situation would be one relay for both high beams, one for lows, one for the driving lights, and one for the tail/clearance lights.


[This message has been edited by bill h (edited September 26, 2005).]

Bill,
Your suggestions are right on target, but let me add some additional suggestions.

I had dim headlights for years...even took my unit to Barth way back when for a complete fix, but they were unable to improve them at all. Finally found out that while there were many problems, the REAL problem was the ground circuit. They used a single (and long) 12gage wire to supply the ground side! So, I ripped out all the wiring, installed twin Bosch 40A relays with a 10gage wire per bulb on the hot side and another 10gage wire for EACH bulb ground. I mounted the relays very close to the headlights to further reduce losses. The headlight switch now carries only the relay coil current, so it runs cool and my dash lights are now twice as bright. I also replaced the halogen bulbs with high-output halogens. Now, we can run at night in the rain on blacktop (my old worst nightmare) with few vision problems.

Thanks Bill and Hank,

This headlight thing has really bothered me. And Hank, I ditto the blacktop on a rainy night. When we came into Mackinaw at night in a rainstorm, I was freaking out. Sure glad I had a co-captain like Deb with me and here trusty Earthmate.

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Right now, Kragen has a $20 rebate on a pair of Sylvania Silverstar bulbs. They are the good ones, made in Germany. They are the best I have found.

Here are the ultimate headlight units. For aroung $500 they should be!

http://www.brightheadlights-hid.com/HID_HEADLIGHTS.htm