Help...Help...

[burb71]

When I plug in my headlight switch in it drains my battery over night.
Anyone have an idea why?

[RustyPile]

If your light wiring is unaltered, no relays, warning buzzers, etc, Check to be sure the dome light isn't turned on.

[burb71]

Originally Posted by RustyPile

If your light wiring is unaltered, no relays, warning buzzers, etc, Check to be sure the dome light isn't turned on.

The dome light only comes on if I turn it on, No relays or anything.

[Palf70Step]

Possibly a short in floor dimmer switch.

[burb71]

Originally Posted by Palf70Step

Possibly a short in floor dimmer switch.

Are you thinking it may be the dimmer switch itself or the wiring leading to the switch?

[leftybass209]

Time to get out your multimeter and chase down one of the well done schematics on this site!

You can do a parasitic draw test, to isolate which circuit may be causing the issue, and would also help isolate a lot of other potential draws. There's write ups to search if you don't know how.

Do check the basics like grounds though. Are all the ground straps in place, clean, and making decent connections. Side note, Ford Explorers (can't remember the years) have decent push on ground straps under the frames, easy to pull, and work like a charm on our trucks.

[burb71]

Originally Posted by leftybass209

Time to get out your multimeter and chase down one of the well done schematics on this site!

You can do a parasitic draw test, to isolate which circuit may be causing the issue, and would also help isolate a lot of other potential draws. There's write ups to search if you don't know how.

Do check the basics like grounds though. Are all the ground straps in place, clean, and making decent connections. Side note, Ford Explorers (can't remember the years) have decent push on ground straps under the frames, easy to pull, and work like a charm on our trucks.

I recently reinstalled all the ground straps after Partial disassembly of the truck for Blasting the frame & painting.

[RustyPile]

Originally Posted by burb71

Are you thinking it may be the dimmer switch itself or the wiring leading to the switch?

Under normal circumstances, voltage appears at the dimmer switch only when the light switch is pulled to the ON position. If the switch is OFF and you have voltage on the dimmer switch, the fault is not with the dimmer switch. Power is somehow being "transferred" from another source. There is no "cut and dried" solution to your problem. Understanding how the electrical system works and the skill to troubleshoot are your best tools. Do you have a wiring schematic/diagram of your truck??

Before we assume anything and go running down rabbit holes. Are any fuses being blown? Have you tried disconnecting a battery cable and jumpering a test light between the battery post and the cable? Do you know how to run this test??

[burb71]

No fuses are being blown, and no I don't know how to conduct that test.

[RustyPile]

Originally Posted by burb71

No fuses are being blown, and no I don't know how to conduct that test.

Use a test light that is equipped with an incandescent bulb, not an LED. For our purposes, a cheap light will work as well as an expensive one. The important thing is that it has an incandescent bulb NOT AN LED. A DVM will work for this test, but it is more complicated to use. Due to your inexperience with electrical issues, I think a test light will work better. If you don't have a test light, here's a link to various models.

https://www.bing.com/search?q=12+vol...&ocid=msedgdhp

The easiest way to conduct this test: Disconnect either battery cable from the battery. Connect the test light between the cable and the battery post. plug in the headlight switch but don't turn it on. make sure EVERYTHING electrical is turned off. If you have a drain, the test light wil glow. The brighter the glow, the heavier the drain. If the test light is glowing (no matter how bright), one at a time start removing fuses. Pull a fuse and if the test light continues to glow, move on to the next fuse. When you remove a fuse that causes the test light to go out, that's the circuit that produces the drain.

Areas to pay special attention. Dome light, glove compartment light, bad, or turned on dome light switches, sound systems, horn relay, relays that are not stock (factory installed).

Come back and tell us what you find. We'll tell you what to do next.

[BigBird05]

How old is your head light switch?

[burb71]

Originally Posted by BigBird05

How old is your head light switch?

It's a new headlight switch, I'm using the original dimmer switch though.

[leftybass209]

Originally Posted by burb71

It's a new headlight switch, I'm using the original dimmer switch though.

I don't like being a parts replacer without understanding why it needs replacing but with a dimmer...

They weren't great new and often needed replacing multiple times in the lifespan of a truck. Moisture on your shoes, plugged vents that rust rockers right next to the switch, and many years can cause corrosion, high resistance, etc.

In this case I'd replace the dimmer for peace of mind and being relatively inexpensive

However, I also wouldn't rule out a cheap or defective replacement headlight switch either... and that's one reason I hate just throwing money at s problem without confirmation.

Definitely learn some basics with a multimeter. You don't have to completely understand why you're doing a given test, and can still be very effective at narrowing down electrical gremlins.

[Caddylackn]

whatever is drawing the power and shorting to ground is getting warm or hot. Leave it on for five minutes then feel around and find out what is drawing power.

[burb71]

Originally Posted by Caddylackn

whatever is drawing the power and shorting to ground is getting warm or hot. Leave it on for five minutes then feel around and find out what is drawing power.

OK this is something I can try, thanks

[Stocker]

You can use a test light instead of a VOM if you're more comfortable with it. Pull a fuse (or open a connector) and close the gap with a test light. If it lights up, even dimly, there's your current draw.

[Palf70Step]

Had a thought, check headlight switch to make sure it is not twisted to turn on the interior lights. Other than that it is time to check for draws associated with the headlight switch area.