I came home from a three week vacation, and now my truck has a rare intermittent. When I turn the key, nothing happens. So, of course, I release the key and repeat and the starter engages and the truck starts normally. I consider the entire starting system as a relatively simple system of switches, interlocks, relays and solenoid. The “problem” is that this happens so intermittently, and always starts on the second twist of the key. There is no opportunity to do any of the standard tests, and changing a part doesn’t prove anything. Thus, I think a “real” mechanic would fix this by using their experience to make a good guess. Any other ideas?
Probe the ignition switch and the starter solenoid at the same time. Try to replicate the no crank… voltage from the switch? No? Replace ignition switch. Voltage at the switch and the starter? Yes? Pull the starter and have it tested and replaced. No? Look for a starter relay, if it has one, replace it. If not, did further into the wiring diagrams.
Given it is nearly 30, corroded grounds could play a part, too.
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A worn park/neutral safety switch can act like that.
Tester
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Manual transmission. I do not exercise the clutch pedal in-between the two key twists.
I guess that temporarily jumping that switch would help the diagnosis.
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The starter was replaced about 8 years ago. The other components are all original. I don’t recall whether the starter solenoid was integral with the starter. I think it was.
Then the clutch pedal inter-lock switch.
Tester
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I’ll shoot from the hip and guess that the starter solenoid is near failing. The pieces to repair the solenoid are available for a few dollars for anyone who feels confident they can do the repair. Of course the starter itself could fail soon.
To eliminate all all the possible external switches remove the starter and bench test it. Of course most McParts stores will bench test starters for free, Call around your area for a store that stocks your part and tests your starter.Good Luck.
BTW, I still Have a can full of all the various solenoid contacts that someone is welcome to.
For whatever reason Ford ran a fender mounted stater solenoid as well as a stater mounted solenoid, I think yours is one of the years Ford did that…
Never seen two starter solenoids on a Ford.
I wonder the purpose?
I stand corrected.
Tester
I have seen it multiple times…
Like I said “For whatever reason Ford ran…”
I have no idea why, but I think it was in the transition time that Ford was moving towards the starter motor only solenoid time…
I do know the 1st time I went to check a no crank on one I was confused when I saw the set up… lol
EDIT: With the double Solenoids, the one on the fender is called a relay, but it is the old solenoid…
I went through this on a 1997 Ford F250 for quite a while. It is a manual transmission so was finding myself always parking it where I could roll start it. I went through several starters as well since the solenoid burned up.
Then I found this bulletin online that stated “Corroded solenoid wires cause intermittent start issues on Mazda and Ford vehicles between X an Y years.” My 1997 was in the year range. I went out at cut off the end of the solenoid signal wire and it was black, corroded, and crumbling inside. I ended up cutting off several feet of wire and replacing it with marine grade wire from a junk trolling motor. This wire is heavier gauge and corrosion resistant so better than what came on the truck. Cut off an inch down there and see what it gets you. If black and corroded, keep cutting until you hit solid bright copper wire. I cut several feet off and was nearing the firewall by the time I found good wire.
I cannot find the article that told about the exact problem but apparently it is common as I found others with it online when searching just now. Either way, this was without a doubt the cause of my troubles as it has never skipped a beat since.
Your first picture is not of a solenoid, it’s just a heavy duty relay. A solenoid provides some mechanical motion to move something external to it.
I am getting some useful hints here. I need to be clearer about one symptom. The problem was much worse on the first two days away. Since then, it has become far more infrequent. And, no, it is not a weak battery, since it turns over strongly when it turns over, and absolute silence (no click, click, click) when it won’t turn over.
Also, I checked. I have the two solenoids. Since one is used as a relay, it means I don’t need to go looking elsewhere for a box full of relays to check.
So, I appreciate all the suggestions. One more question: the clutch in/out switch has a plug with about 6-8 wires going to it. What are they all doing?
Ask your shop to measure the voltage on the thinner of the two wires that connect to the solenoid directly attached to the starter motor itself. It is labeled “s” in DMP’s diagram above. When the key is in “start” it should measure at least 10.5 volts. Probe between the terminal on the starter motor and the starter motor case. What voltage does it measure?
No idea. I’d only expect two wires connected to the clutch safety switch. You’re talking about the switch near the clutch pedal support, right? Perhaps that’s just a wiring harness sub-assembly & some of the wires just pass through on their way to somewhere else , have nothing to do with the clutch switch.
Does your truck have the anti-theft option? If so, that may be what’s causing the problem. It seems to prevent cranking the engine when in anti-theft-mode. .
Another area to check is worn ignition switch mounted at the base of the steering column.
Tester
So, armed with an electrical diagram and some good ideas, I have a good idea of where to look. However, the rare intermittent nature of this problem means that I cannot pinpoint the problem, because it doesn’t stay broken.
I can check the hot side voltages, and I will surely look for the corroded wire issue. Otherwise I have the luxury of waiting until the problem gets worse.
Sometimes we just replace parts. I guess I would be first looking at that relay/solenoid and either replace or check the wires as noted above. Three weeks of sitting could have caused some corrosion to build up. If you replace it though and the wires are still funky, same problem, so the cheap thing would be to check the wires first. Hearing no click though seems to suggest the problem is up stream of the starter/solenoid since no power seems to be getting to it.
Suggest to start by making sure both connections at the battery posts are clean and shiny & and properly tightened.