I want to use the factory cargo light switch to power a 10" Rigid LED light bar that I'm installing in my headache rack to use as a backup light. Any ideas on where the easiest place to tap into this switch might be? If I can get to it from under the hood or somewhere else instead of running another wire through the firewall that would be great.

I don't need to retain use of the factory cargo light since it's blocked by my headache rack, so that isn't an issue.

 

Hoss, the wire coming off of your dash switch just provides a momentary ground to the computer (computer then latching a relay). I went all through that system trying to control a solenoid for a transfer tank pump, even wiring in a solid state controller ahead of the solenoid. What I ran into is every time I unlocked my doors there was a voltage felt on that same wire and when the dome light came on and off I heard my solenoid latching. If you were crafty with some diodes you could probably pull it off. The multiplexing they have engineered into these rigs makes it difficult to run aftermarket accessories from factory switches. I ended up getting a controller from off road engineering that takes a momentary ground from a push button switch I put in my dash and that controls my fuel pump solenoid. There is only one wire going through the firewall. The other side of the switch is grounded under the dash. Good luck bud.

 

Thanks for the info. As much as I like the idea, that almost sounds more complicated than its worth. Maybe I'll just install a seperate switch for the rear light. I didn't really think about that light coming on when you unlock the doors. As bright as the LED light bars are, I'd really hate for it to come on except when I specifically want it to.

 

I think Ram is using a CAN-BUS system on the newer Ram trucks. I have read enough horror stories were people have added auxiliary lighting and or switches that have failed the TIPM boxes on their trucks. Replacement costs are in the $600 range from what I have seen that has been posted. If this was me I would added an auxiliary power source and switch for the LED’s on your truck.

When I added my air bags and compressor for the air bags I used a Painless Wiring Auxiliary fuse block and relay from Geno’s Garage. They offer either a 3 circuit or 7 circuit wiring block and you can choose what style such as Weather Resistant and deferent circuit configurations; such as all hot or some hot and ignition hot. Price ranges from $55.95 to $93.95 depending on style of block ordered. A lot cheaper than what a TPIM would cost to replace.

Just my $0.02.
Jim W.

 

I'm not sure what a TPIM is, but thus far all of the auxiliary items added to my truck have had relays and they've been connected directly to the battery. I suppose that's how I'll connect the new backup light as well. I like the idea of some sort of circuit board though. I may have to look into that just for the sake of cleaning things up a bit under my hood.

 

The TIPM is your Totally Integrated Power Module; this controls all of the electrical functions on the truck.
Jim W.

 

Thanks for the info. But...

If you're wiring up auxiliary lighting that's completely separate from from the TPIM then how could it cause it to fail? My HID conversions are a little different in that they tie into the wiring harness for the headlights and fog lights (only for activation...they're powered directly from the batteries). My LED's and air bag controller are all powered directly from the battery. I'm assuming the truck doesn't even know they're there.

 

Yes, this will not cause an issue with the TIPM but I was originally informing you about using a power switch in the cab in your first thread to power the LED light bar.

Jim W.

 

Gotcha. Thanks for the info. I'm just gonna forget that idea and install the switch that came with the light.