Check Engine Light with Dakota Digital

[Pechin0351]

I looked around and saw some of y’all talking about this in the past, but didn’t really see a resolution. So here we go:
Wild Horses EFI Harness, 5.0, A9M ECU, AAW wiring harnesses, Dakota Digital HDX gauge.

Okay so I have been hooking stuff up, truck runs great, isles great, all that. The CEL is direct wired from the EFI harness to the DD gauge control box. My CEL is always on, and I can’t get it to flash for a test mode. I do not have a secondary light hooked up.
Does this require a larger load? Maybe a pull-up resistor to 12V, or a incandescent light? I did try hooking up an LED with a resistor with it to 12V but that’s a tiny load. What did I miss, how did you guys running a Digital gauge with CEL do it?
Thanks



UPDATE:
I found that my issue was a burned trace inside the ECU. Checking resistance between the test connector wire (Pin 46) and the ground side of the battery terminal should result in a very low resistance. Mine was sitting around 2.2K OHMS. Since Pin 46 just connects to the ground through the ECU, I tore it open and found the burned trace, pictures are below. Soldering a wire to fix the broken trace solved my problem.

 

[73azbronco]

I'd call dakota their staff is pretty helpful when i called on another issue.

 

[Pechin0351]

Thanks for the reply, they are closed right now, so maybe tomorrow if I don’t find a resolution through here.

 

[Jebus]

Seperate the CEL wire and hook it to an regular test light. The CEL wire is the sink, so 12v to other side of test light. If CEL still stays on and you can not run self test, IIRC, there are bad caps in your ECU.

Memory Edit: A quick google search shows a possible burned trace in the ECU if CEL stays on and no self test.

You say it runs good. Auto or Manual. Some posts point to a miswired interlock circuit for starting.

 

[Pechin0351]

Thanks for the reply Jebus. I was screwing around some and searching Fox Body forums and found some further info. I should have continuity between my test port “ECU Wire 46” and battery ground. But I do not. Which means the trace from inside the ECU is probably damaged, like you mentioned Jebus. So I took my ECU apart and found on the underside that the trace does run to an SMD cap, and beyond. But between the pin and the cap, the trace is indeed fried. I’ll repair it in the AM and investigate further.

 

[904Bronco]

If the WH's EFI harness is made by Ron Francis then there are two (red and tan) wires that run for a standard MIL light. Red has voltage and is not used with the DD gauge. The directions say to terminate the red wire safely and only use the tan wire connected to the DD connection on the box.

 

[Pechin0351]

I also believe the Wild Horses one is an RJM harness. And I did wire it per the instructions. I was just asking if anyone had to load the line with a light for it to work properly (or a resistor). I did say in my comment last night that I believe I found the issue to be a burned trace on my ECU. I will repair it this morning and report back.

 

[Pechin0351]

Welp the trace was indeed fried. I use a small bit of 30 gauge wire, and Pin 46 is now connected to 60 and 40 again (ECU ground) I am sure this will fix my issue.

 

[904Bronco]

I also believe the Wild Horses one is an RJM harness. And I did wire it per the instructions. I was just asking if anyone had to load the line with a light for it to work properly (or a resistor). I did say in my comment last night that I believe I found the issue to be a burned trace on my ECU. I will repair it this morning and report back.

Ron Francis basically took the the RJM design and sold it as theirs. Not sure how that deal with Ryan was worked out. He had some rough times at the close of his business.

I am thinking that you may have found the problem... I just did pretty much the same rewire job you have done, so everything is fresh in my mind. It is good to document certain things for the next group of folks that come behind us. And it was really important to read everyone's installation instructions before starting... Like adding a constant hot to the AAW harness for the DD gauge set which isn't there.

Looking forward to hear that you rig is up and running.

 

[Pechin0351]

Ron Francis basically took the the RJM design and sold it as theirs. Not sure how that deal with Ryan was worked out. He had some rough times at the close of his business.

I am thinking that you may have found the problem... I just did pretty much the same rewire job you have done, so everything is fresh in my mind. It is good to document certain things for the next group of folks that come behind us. And it was really important to read everyone's installation instructions before starting... Like adding a constant hot to the AAW harness for the DD gauge set which isn't there.

Looking forward to hear that you rig is up and running.

Yessir! That did fix my issue. I pulled codes just fine. So, no pull up or any fancy loading seems to be required.
I did change some wiring around on my AAW, I added a constant hot, I rerouted the neutral safety switch/starter wiring (no point having it go all the way to the driver side just to go back to my solenoid) I took a few wires out, and added a few. The truck seems to run great, I actually drove it around the drive way a few times for my first time last weekend. That bronco has not moved on pavement under its own power since 1994.
I am going to edit my original post with my findings.