I did some work on my truck yesterday. I had the sensors for the trans temp and EGT gauges installed, but I needed to do the rest of the work to get the gauges wired in. I also wanted to install my new brake controller to replace the old one - both aftermarket. The gauges' power comes from the #5 circuit on my truck, which is #29 on later trucks and is the 10A customer access circuit. There was nothing on it when I started. The brake controller is wired into the factory brake controller wiring that the previous controller used.

I wired the gauges, lights, and sensors and the EGT works fine. The trans temp gauge sort of works. It doesn't really get that high on the scale, maybe to 110 or so. I drove around town last night to get fuel and see how the gauges worked and it never really went past there. I have a 6.0 cooler but I don't think it can be doing that good of a job. It does read colder when I first start it though.

So that's problem (?) #1.

Problem #2 is a little worse - I suddenly have no turn signals or hazard flashers. They were working before. My owner's manual doesn't say which fuse is for the turn signal flashers, if the hazards and turn signals share the same relay, or much else of any use at all. Where to start with this one?

Problem #3 - my new brake controller appears to be dead. It has power (used a voltmeter) and I'm pretty sure I wired it right. I matched up the colors (red, white, blue) except the Ford side had a tiny green wire for ground and the brake controller had a black #10 wire. I ran them both to the same ground on the frame that I grounded the gauges and gauge lights to. When I turn the ignition on, it doesn't power up or indicate it's doing anything and according to the manual, it should tell me when the trailer isn't connected. It's a Tekonsha P3. The previous brake controller, as poor of a job it did, functioned when wired the same way.

 

Anybody???

 

Little busy now but I'll read through this again when I get more time and see what's up.

For now, where did you mount the trans temp probe? In the port on the left side of the trans behind the electrical connector?

 

Time arrived sooner than expected, thank you Mexican food for dinner. Yes indeed - this is a potty post, hah.

#1 - Just to reference my first post, location of the temperature probe? When I first did mine I didn't know about the test port on the transmission so I used that stupid bracket that holds the probe against a trans cooler line. Ridiculously stupid contraption, trying to read temps through the hard line. I would barely see 115° after long freeway blasts. Relocated it to the test port and now it registers perfectly.

The 6.0 cooler does an amazing job. Razzi barely sees 150-160° rolling around Houston in the 100°+ summers in stop and go traffic, when the trans will be making the most heat. I took a peek at the weather in Sacramento and it shows 60-70° the past few days. Given that for OAT, and if you just moseyed around town I'd say it's working just fine if the probe is in the test port.

#2 - Try checking your flasher relay. I had the same problem with mine and it just turned out to be the relay had crapped out suddenly. The first tip off to me was the lack of the turn signal clicking when activating the blinkers or hazards, the relay should be where the sound comes from IIRC. Enil01 had the same problem on his '06 E350 and it was also the flasher relay. I'd start there and see if it's still good, should be relatively cheap at a parts store.

#3 - Did your rig not have the factory connector under the dash center stack on the driver's side? When I installed my Prodigy I was not looking forwards to wiring it in, then I found that connector after searching on here a little bit. It's a gray square plug, just inside a hole on by your right knee when you drop the fuse panel cover under the steering wheel.
The only thing I can think of is maybe the internals on your new P3 require a slightly different grounding path. If I read your post right, what I understand is you grounded the Ford green wire and the black wire from the controller to the frame instead of just hooking them to each other? From what I understand the Ford wire should already be grounded, so you may just be grounding the ground again and it might be causing issues with the circuit. Not positive but it's a start.

 

Thank you Matt and Jose.

I used the test port on the side of the transmission right above the connector. I'm heading for a longer trip with some 1500' elevation changes in a bit so I'll see how it does.

Ok, good to know.

There's a youtube video showing the location of the flasher. Looks like fun.

I didn't really follow the wires back up, but the PO had a brake controller, and the four wires were just tied up under the dash. I just wired in my old controller and it worked fine.

As far as I know, which is far from everything when it comes to electronics, you can never have too good of a ground. You can, however, have inadequate ground, which is what I was trying to prevent by tying both grounds together at the frame. The prodigy ground was #10 wire and the Ford ground was about #18. It did not feel right to connect these two wires together. I could be convinced I'm completely wrong though.

 

The trans temp gauge works, but I haven't gotten it to read any higher than 125 or so. I guess the 6.0 cooler really does do that good of a job.

The EGT works well. I got it as high as 1000* unloaded going up a 1500' climb (not that I was trying)

Is a parts store aftermarket flasher ok to use or should I get one from Ford?

 

Big name brand aftermarket electrical components I am far more comfortable with compared to the cheaper options. Of couture I recommend OEM, but if those are just sourced from the same supplier as the big name items... don't make much difference then.

 

I had the same problem the other day. Suddenly no turns but had hazard. Bad ep27 led relay. Replaced it. Fixed.

 

I pulled the dash apart today to change the flasher relay - which was $40 from Ford because I didn't want to wait - and found that I still had no flashers or hazards. I was about to run back inside and scream for help on here, but I decided to go through the fuse box just in case. I found fuse #13, a 20-amp, blown. I replaced it and now I have an extra flasher relay.

I think I'm going to RMA the controller and get another one. There's no reason it shouldn't be working.