I'm in the process of completely rewiring my truck when I took the headlight switch off it had 6V 20A wrote on the top of it. I brought it about 13 years ago from carptener's in NC, I asked for a 12 V. The question is, is there a difference in the two, I've never had any problems with the headlights except the instrument panel lights went out so I just wired them to the park lights.

 

Didn't we just talk about this and we were all in agreement that you were going to use your original switch?


https://www.ford-trucks.com/dcforum/48_60/1536.html

 

Just to be on the safe side use the 56 switch i did on my 54.

 

The original switch I was referring to was the one I thought was a 12V that I brought years ago. I just took all the wire out today and saw the 6V on the top of the switch.

 

jaye,

Many electrical switches are rated for multiple voltages and currents. For example, you can buy a 125 VAC, 1 A switch that is rated at 2 A at 24 VDC. At low DC voltages, the current rating probably doesn't change much as you increase the voltage. A switch rated at 20 A for 6 VDC might very well be rated at the same 20 A at 12 VDC.

If you are really concerned, a simple test is to measure the voltage drop across the switch with the lights on. Get a voltmeter and measure the voltage between the 12 V input to the switch and the output to the headlights. Make sure you measure the voltage right at the switch terminals so you don't count the voltage drop in the wiring harness. If the voltage drop you measure across the switch is less than 0.1 V you have nothing to worry about since the switch power dissipation is only 1.2 Watts which it should handle easily. The 0.1 V drop won't make a noticable difference in your headlight brightness since your system voltage varies by considerably more than 0.1 V with engine speed and electrical load.

Earl

 

The switch power dissipation I mentioned in the previous post should be 2 W (20 A x 0.1 V), NOT 1.2 W. A standard headlight switch should still handle 2 W without any trouble.

Earl