1988 f350 tach wiring

[clayhwalker]

I have a 1988 F350 that originally had an IDI in it that I swapped a 5.9 Cummins into. I’m trying to get my factory tack to work but in all the wiring diagrams I have none of them have what wire goes to the tack. I have a Dakota digital switch to make it work but I can’t figure out which wire I need to hook it up too. Any help would be greatly appreciated.

 

[IDIBOBS]

Awww the problem with bad wiring job.

 

[KansasIDI]

I have a 1988 F350 that originally had an IDI in it that I swapped a 5.9 Cummins into. I’m trying to get my factory tack to work but in all the wiring diagrams I have none of them have what wire goes to the tack. I have a Dakota digital switch to make it work but I can’t figure out which wire I need to hook it up too. Any help would be greatly appreciated.

My understanding is that the 5.9 Cummins speed sensor is in the alternator. Which alternator did you use? Not all of them had the speed sensor, as 89-93 Dodge trucks didn’t have a tach. 94-onward all had a tach. Also, with these swaps, some people use a Ford alternator.

Have you been able to find any other information about your tach source?

They’re kinda cluttery, and I know not everyone uses Facebook, but there’s some Cummins conversion pages over there with good information and some helpful people. Plenty of clutter though, it’s Facebook.

 

[clayhwalker]

I am using the one wire Ford alternator that’s a upgrade from stock. I have been on the phone with Dakota digital and did some troubleshooting and I have a signal coming from the alternator through the Dakota digital box but I cannot figure out which wire going into either the A or B plug in the back of the cluster feeds my alternator. That’s what I’m trying to figure out. I have the wiring schematics from Ford but none of the wires going into the A or B plug are the same circuit as the tech feed on the schematic. And this is why I hate doing wiring.

 

[WMO4IDI]

Check out this pdf, pins A6 (tach signal, Dark Green/Yellow), A13 (12V constant, Red/Yellow) & B2 (Ground, Black) are involved.

 

[clayhwalker]

That is exactly what I was looking for

 

[clayhwalker]

Well after closer inspection of the cluster circuit board I can see I need a new one. It is starting to fall apart. Does anyone have info on if the E9TF-10C956-B is compatible with E8TF-10C956-B. I can find plenty of the E9TF but no E8TF on ebay.