This weekend I decided to re-do the wiring for my back up lights since the switch wasn't working. I decided to tap into the reverse lights so the lights would come on whenever I am in reverse. I got everything wired up with 16 gauge wiring, a 40 amp relay, and a 20 amp in-line fuse. Put it in reverse and nothing. Then I decided to just wire it up to a switch really quick to see if the lights had just gone bad over time and plugged in the ground, then the load, and then the power and the fuse blew instantly. I was tired of messing around so I ditched the fuse and turned them on. Walked to the back of the truck because I didn't see any light and saw the lights on very dim and smoking like crazy, went to the front and the wiring starting at the switch was burning through and smoking like crazy. What did I do wrong that all of this happened from start to finish?

 

Sounds like you shorted a wire somewhere. Did you get your grounds mixed up? All connections clean and secured?

 

If you wired them up direct, something is wrong with the lamps.

time to start over with a new setup, considering the wire from the cab ( sounds like the cab is where the switch is at ) to the rear of the truck is most likely damaged.

This sounds like what you want



Is the switch an illuminated switch ? Sounds like you might have used the wrong pin numbers on it ( i.e. trying to run the aux lamps through the indicator on the switch ?? ).

If the lights did nothing when plugged in directly, there could be an issue with them. Are they full wiring harness ( ground & power ) or the cheap type that just use the mounting blot to self ground ?
If they are a full wiring harness, do you have it installed the correct direction ? ( the ground wire might be common to the mounting lug, and the paint on the mount was acting like a high resistance ground ).

Do not count trying to run the lamps directly from the truck's reverse lamps as a test, the DTR ( Digital Transmission Range ) Sensor is not mean to run anymore load than the truck's reverse lamps ( it will not even drive 1A more load ).

Start by replacing the wiring from the switch to the rear of the truck, and installing the relay, do not plug in the lamps and watch your fuse size 20A is quite large for aux lamps. 2 55W aux lamps draw a total of 8.7 A worse case, so a 10A fuse is large enough ( just shy of the 80% rule ). Make sure to fuse the circuit from what you are using for the always on power to the switch with a 1 A switch.

Once you get to this point, you can turn on the switch, which will only activate the relay. Check the output of the relay for power with a meter.

Sounds like misplaced terminals on the switch and maybe the relay as to why you had the electrical fire starting. Also what ever you had the switch to, you are going to need to check that wire as well, you might have burned up some factory wiring in the process.

 

I just plugged in a switch right by the relay in the engine. I plugged in the ground to the ground, the power to the power, and the lights to the load; I believe that's the right way. The lights are a full wiring harness and are grounded using the factory ground. What is the purpose of a 1 A switch, and where can I get one at? Thanks for the replies guys!

 

Plugged in by what relay and where ?

Are you sure of the pin out on the relay ?

What factory ground are you talking about ?

The 1A switch, I meant to post 1 A inline fuse to the switch.

 

WhenI plugged it directly into the switch I was not using the relay. What are the corresponding numbers on the relay for the ground, power, load, and switch? The factory ground used for the relay is the one right behind the battery, and the factory ground used for the lights is the ground for the wiring that is farthest back on the inner frame.

 

The numbers on the relay can change, depending if the manufacture sticks with the standard numbering.

Std Automotive


The 1/2 ISO numbering ( used by some mfgrs on full size relays).


You might have the picture type, which some of them the icons are a bit dodgy at times.

 

I have tomorrow off of work so I am going to get some new lights and add in new wire and get this figured out!

 

Cannot stress enough.

Install the system, but leave the leads to the lamps disconnected.

Once you get to this point, install the fuse, and check for the symptoms again.

If this is good, use a meter to verify operation at the end of the wire that is going to plug into the lamps for correct polarity.

 

Rewired it, plugged the ground, lead and power into the relay and found my problem. I was working on it when it was dark out the other night and misread the numbers on the relay. I have power now and I will be installing the lights on Friday when I have access to the garage. Thank you so much for all the help, much appreciated.

 

Glad it was an easy enough item to fix.

That happens, the raised black lettering on a black base can be a challenge to read at time.

 

Got it all completely finished today and I couldn't be happier, thanks for all the help SSCULLY.