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Trouble with light switches

Sojo2600

Sojo2600

Rank III
Member

Enthusiast I

Hey, all.

I recently added a lightbar to my rig and it came with a wiring harness and a couple of switches since it’s a combo white/amber bar. I want to use new switches that are “OEM style” which fit directly into the factory dashboard cutouts.

Unfortunately I am running into an issue where the wires start heating up after I connect them to the new switches. I don’t have much wiring experience, so I don’t know what I’m doing wrong.

One big difference is that the switches that came with the harness have 3 terminals and the OEM style switches only have two. I am operating under the assumption that the third terminal is for powering the light within the switches themselves. This would explain why the OEM switches only have 2 terminals since they do not have a light. I tried connecting the red and black wires to the OEM switches in every configuration possible, but it always results in the wires building up resistance and overheating. Any ideas what I am doing wrong?
 

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Flipper

Flipper

Rank V
Launch Member

Member III

If they are simple on/off lighted rocker switches (SPST) the extra post is for the ground for the light inside the switch. If it is wired correctly and the wires are getting warm the lights are drawing too much current (amps) . If this is the case you will have to install a relay for the lights. A simple relay diagram can be found on the net.
 
Sojo2600

Sojo2600

Rank III
Member

Enthusiast I

Thank you for your replies, Flipper and kwill. The switches with 3 terminals came with the harness and have their own on/off indicator lights. These switches work fine and the harness came pre-wired with a relay for them. It’s when I try to use the switches without a light and only two terminals that I get the hot wire issue.
 
K

kwill

Rank II

Enthusiast III

I'm no wiring expert so I'm not sure what is going wrong. It sounds like somehow the relay is being bypassed when you use the OEM style switches. I recommend studying some of the websites and YouTube videos made by people that know what they're doing.
 
Boostpowered

Boostpowered

Rank VI

Member III

Here is how they need to be wired you may want to check that the relay is wired correctly. It can be done because I've done quite a few of those cheap lightbars. Is it popping the fuse during the overheating wire issue? Either diagram can be used pin 85 and 86 on the relay are interchangeable as to which takes ground or power. Take your battery out and wire everything up out of the truck to check function.

download.jpeg-27.jpgdownload.jpeg-26.jpg
 
Sojo2600

Sojo2600

Rank III
Member

Enthusiast I

Sounds like I should study how the harness is wired to see which wires are going where. The dual switch setup adds a little bit of complexity, but should be solvable.

Is there any possibility that the OEM switches allow more power to flow than the wires can handle, or is my issue definitely just a short being introduced?
 
K

kwill

Rank II

Enthusiast III

Is there any possibility that the OEM switches allow more power to flow than the wires can handle, or is my issue definitely just a short being introduced?
Click to expand...
I think the answer is neither; the lights pull a big amperage and the switch and the wire to the switch cannot carry that load without overheating. Seriously, this is how cars burn to the ground.
 
Sojo2600

Sojo2600

Rank III
Member

Enthusiast I

Based on both of the wiring diagrams that Boostpowered provided and what I have found online, it seems like a simple on/off switch doesn't need the ground wire, that's already covered via the relay. Here's the best page I found which displays wiring diagrams for both 2 post and 3 post (lighted) switches: On/Off Switch & LED Rocker Switch Wiring Diagrams | Oznium That being said, I decided to order the OEM style switches with lights that have 3 posts on them. Might as well keep the wiring as similar as possible.
 
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Sojo2600

Sojo2600

Rank III
Member

Enthusiast I

Im posting a followup, in case anyone else finds themselves in this situation and is reading this in the future. Connecting the red battery wire and the colored accessory wire was the correct combination for the 2-post on/off switch. The ground wires are only necessary for the 3-post switches which light up.
 
Kozysnack

Kozysnack

Rank VII
Member
Investor

Expedition Master I

Sojo2600 said:
Im posting a followup, in case anyone else finds themselves in this situation and is reading this in the future. Connecting the red battery wire and the colored accessory wire was the correct combination for the 2-post on/off switch. The ground wires are only necessary for the 3-post switches which light up.
Click to expand...
thats for getting this thread started I was about to ask this same question then searched the forum for keyword Lightbar and wham all this info is out here!
 
Sojo2600

Sojo2600

Rank III
Member

Enthusiast I

Kozysnack said:
Sojo2600 said:
Im posting a followup, in case anyone else finds themselves in this situation and is reading this in the future. Connecting the red battery wire and the colored accessory wire was the correct combination for the 2-post on/off switch. The ground wires are only necessary for the 3-post switches which light up.
Click to expand...
thats for getting this thread started I was about to ask this same question then searched the forum for keyword Lightbar and wham all this info is out here!
Click to expand...
Great, I’m glad that it helped!
 
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