voltage to starter solenoid trigger wire in run position
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5th Wheeling
Joined: Dec 2014
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voltage to starter solenoid trigger wire in run position
I have a 1987 f-150 with 300 six and efi, t-18 four speed no cruise. The clutch interlock is located on the clutch pedal and has three wires going to it. On one side we have two wires connected together….a red with blue stripe and a black(I think) with white stripe (this one is also a smaller gauge). On the other side is solid red. On the red with blue stripe side I see 0v in start or run until I depressed the clutch pedal then I got 7V in run and start. There is a push button type switch that the clutch pedal contacts that is causing the switching from 0 to 7. On the red side I got 0V in run and 12V in start (didn’t matter what I was doing with the clutch pedal). Does this mean the 7V is back feeding on black with white stripe?
pedant
Joined: Jan 2008
Posts: 23,576
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From: EXTREME southwest CT
It means your clutch safety interlock is functioning but showing resistance and maybe corroded.
Do you have a problem getting the starter to engage?
(not to be pedantic but it is a starter *relay* mounted in the right fender)
Does the truck turn over normally if you jumper the S terminal from the battery cable next to it?
Do you have a problem getting the starter to engage?
(not to be pedantic but it is a starter *relay* mounted in the right fender)
Does the truck turn over normally if you jumper the S terminal from the battery cable next to it?
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5th Wheeling
Joined: Dec 2014
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Yes truck turns over normally if you put a screwdriver to the solenoid trigger wire to the side that is connected to battery positive. The problem I am having is that when the truck is cranked with the key it keeps on cranking when returned to the run position because for some reason the trigger wire is still sending 7 volts to the solenoid on the fender. I tried unplgging the coil and distributor and then just the distributor and I still get the 7 volts at trigger wire. I tried disconnecting the interlock switch and test both side to find out which is in and which is out and I am getting 7 volts on the wire that is going to the fender mounted solenoid. So the 7 volts must be coming from the black with white wire. Does this go to the ECM?
Fleet Owner
Joined: Aug 2005
Posts: 23,667
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From: Easton,Ks
The black wire with a white stripe is an information wire going to the computer to let it know the engine is cranking. The 7 volts if you use a loading test light it would not light. Sounds like you are using a DVM to read this 7 volts and you can not believe it in this situation. Yes the stray 7 volts is coming from the computer (ECM).
The starter solenoid on the fender coil should take this 7 volts to zero.
Sounds like you have a bad clutch switch as the 7 volts should go through the clutch switch to the starter solenoid with the clutch not depressed.
You may also have a bad starter solenoid on the fender sticking closed.
Also make sure the starter solenoid on the fender is grounded to the fender and the fender is grounded to the NEG post of the battery.
The starter solenoid on the fender coil should take this 7 volts to zero.
Sounds like you have a bad clutch switch as the 7 volts should go through the clutch switch to the starter solenoid with the clutch not depressed.
You may also have a bad starter solenoid on the fender sticking closed.
Also make sure the starter solenoid on the fender is grounded to the fender and the fender is grounded to the NEG post of the battery.
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