Hey All, I have a 2006 F150 2WD XL with a 4.6 and automatic transmission. We just purchased a trailer and I have added the transmission temperature gauge and engine temperature gauge in the A pillar. My question is, how do I wire my gauge lights into the fuse box. I used an "Add a Fuse" kit for the gauge power source and tapped into fuse 1 10 amp (gauges have power when the truck starts). I used another "Add a Fuse" kit for the gauge illumination power and tapped into fuse 5 15 amp for instrument panel illumination. Even though fuse 5 is a run / accessory, the gauge lights stay on even when the truck is turned off and the key removed. If anyone has already figured out what fuse or under dash wire to tap into for the gauge lights, any suggestions or help would be appreciated.

I have done some searching and found out about the transmission test port for the sending unit, but couldn't find anything about the gauge wiring.

 

I'm not very good with electrical, but I wired my cab lights myself. Those got power from wire #5 on the headlight switch. That is the power to the parking lights. so if you spliced into that wire its guaranteed to only light up the gauges when the truck lights are on

 

Danorules, Thanks for the help. I"ll try wire #5 for the headlamps and run an in line fuse just to be safe. I'll let everyone know how it works.

 

After spending some time with my Haynes manual and a test light, I figured it out. First I removed the headlight switch bezel, which was only held in by three plastic pins. Next I disconnected the electrical connector at the back of the headlight switch. With the truck ignition in the accessory and run position I used a test light and found the red / yellow wire had power when the headlamps were on. I used a blue quick connect splice and got power to my two pillar gauges. Ended up being much easier then I thought.

Now its time to see how hot the transmission gets while daily driving compared to towing our trailer.

 

With the trans temp gauge in I see that under normal driving conditions the trans runs at about 155 to 165. I have not yet pulled my trailer, but can only imagine that the temps will be much higher. I have a huge plate and fin trans cooler to put in after the factory trans cooler, but I want to see how the trans temps are with the trailer before I make the addition.

This could probably go in a new thread, but here goes. We just bought a 6000lb trailer, and I know my F150 is not the optimal tow vehicle especially with the 4.6, but I am thinking about switching out the 8.8 rear end for a 9.75. With four kids and all the gear that goes with them I am already over my weight ratings. Seems to me that the 9.75 with a higher GAWR will increase my tow capacity.

The truck is my DD, with AFE CAI, leveling kit, rear AAL and 33" tires. Since my truck is paid for, I am not considering an F250 / F350 upgrade. I am just looking for more advice on upgrades to make the truck a more capable tow vehicle when needed. Any ideas or thoughts would be appreciated.