Tachometer

[klook]

I have ripped all the ambulance wiring out of my.....ambulance...lol. It provided the tachometer which has started to stop working when I dropped back to an idle. So I want to get another and am wondering about wiring it up. Where to I pick up the signal wire. The original one is still in place but do I use that?

 

[IDIBOBS]

Do you have an E4od or c6?

 

[klook]

E4OD

 

[IDIBOBS]

So with an E4od the tach signal goes from the pick up to the trans controller then to the dash board. So wether you get a stock gauge or a ln aftermarket you need to use the old circuit. Unless you want to run a whole new seperate pick up off the alternator or crack but that’s just dumb nowa days. Most aftermarket diesel tachs have the adjustability to adapt to the stock 700hz at idle signal.

 

[klook]

So I need to buy a tach and then find the wire from the trans controller. I dont have a stock in dash tach. This was a display in the ambulance control board mounted on a custom aluminum extension on the dog house. This was the first year for the Horton system 2000 controller for the module(box). It used a computer to tell everything what to do and when. Older systems were done with relays. I used to have one of those also.

 

[klook]

To further explain, I have rewired the high beams because they went thru the "wig wag" system. I have rewired the marker lights, the compartment lights, and wired up some of the large red rear and side facing lights to come on with the brakes. I am working on recovering the AC and Heat in the module. Last will be the loading lights thru the magnetic switches in the doors.

 

[klook]

Found the rpm signal wire in the compartment behind the driver and tried to use my sounding unit to trace the wire into the cab and dash. Got it traced to behind the drivers seat in a monster loom and lost the signal from there. Does anyone know what wire from the trans control is tach and how do I find the control?

 

[nelstomlinson]

I recommend you get the EVTM, Electrical and Vacuum Troubleshooting Manual, for your vehicle. It won't help with the ambulance stuff, but it'll tell you all about what Ford put in there in the beginning. That's what the ambulance upfitter butchered.