1989; F150; XL; 4X4; 4.9L; EFI; C6 AUTO;
I have a NO CRANK issue and the solution has been avoiding me! LOL
NO power to the ignition wire at the starter relay using the IGNITION (Starter Relay Functions. I can Manually Energise by supplying 12+V or by shorting terminals)
I also have a REVERSE signal issue and these I think are connected to the one fault I am seeing. NO 12V+ down to the AUTO neutral Safety switch (Brand New OEM fitted)
Wires traced through the loom to inside the cabin (both STARTER and NSS wires). No breaks
Does anyone know where the signal for these two circuits originates?
Please NOTE: The Australian version does NOT have the ignition switch mounted on the steering column. It is an actual STD style ignition switch.
Or any other advice checks I should do? The truck was driven in and functioned fine. But now has this issue.

 

"traced the wires through the loom and no breaks"
How about the start signal making it through the neutral safety switch?
Because you listed all the trucks particulars, I can possibly help with a schematic
These are from a 1989 EVTM

 

Your Aussie truck might be different
Either way, the signal from the ignition switch goes through the clutch interlock switch or in your case the neutral safety switch on the side of the C6
If yours has the old style neutral safety switch, it'll be down at the base of the steering column
That's where the old ones were at before they switched the ignition switch to be atop the column
On the ones that have an automatic, sometimes there is a jumper pigtail for the clutch interlock switch wiring above the brake pedal
Same for the stick shifts, there will be jumper wiring under the hood that connects the start wires that would have gone to the C6
I posted that for a 4.9 but should be the same

 

You might have to go back a few years to get a correct schematic for that Aussie truck
Maybe post a picture of your ignition switch and its wiring pigtail

 

Thanks for the reply!
Yes. The Aussie versions are different. The neutral/park safety switch is on the automatic transmission. At the auto’s gear selector shaft.
We have no switches etc on the column like you guys
I don’t get +12v at the neutral/park safety switch. Hence no reverse lights. So I think the no reverse and no crank are related.

 

Superb, thanks you! I will digest these schematics and info
Hopefully I’ll see where the issue is emanating from.
Ive chased the wiring right through the truck and can see a physical problem. Have the instrument cluster out to make tracing easier

Appreciated

 

Ok The clutch interlock pigtail sounds like a place I should look! Didn’t check up there. Makes sense that the loom would be multipurpose and set up for other options etc.
I will check that first thing in the morning 👍

Thanks again.

 

manicmechanic007
OK. Managed to get to the wiring loom over the weekend. No clutch interlock wiring/connectores etc. located. Loom is very clean on connections etc. in the drivers area. Just the usual culprits of brake switch and foot park brake switch. So I am stoill on teh Hunt! Will get soem more diagnostic stuff this week.

Thanks for your help