OK....jumping dind't work.....actually didn't think it would because I had continuity.

Can't figure what would be between the clutch switch and the solenoid?

I'm gonna try to find a schematic......I thought this would be easy

 

So you jumpered the two wires, then turned the key to START and nothing happened? Or did you jumper the one to 12v instead?
If you just put them together and nothing else, then that would not have worked.

I'm thinking that there isn't anything farther downstream to the relay, but the wire itself can fail. So can the connection.
In fact, a very common fault with these old rigs is that the Red w/blue wire connector, which is just a simple 90° push-on thingy, can get lose and stop the process. Usually it's more of an intermittent thing, but can act up in different ways.
When you mess with yours, is it really easy to pull off and kind of sloppy/floppy? If so, gently crimp the connector inside the rubber insulator with a pair of small pliers. And I mean "gently" because it is very easy to crush them. If you do, it's not necessarily it's death knell. Just have to go inside and pry it open again with something round.

So here's something else. You said you were getting 3.5v to the relay on the Red w/blue wire. What are you reading at the connector to the clutch-interlock switch? You should be able to pull the connector and, with someone turning the key, find battery voltage on one of the Red w/blue wires.
If the wire with power-in to the switch is only showing the same 3.5v reading, then it's not the interlock switch, but something farther upstream. Which would be wiring, a connector (if any) or the ignition switch.

By the way... Looking at your starter relay pic again, your battery cable is properly corroded. Looks like it's been cleaned, because it's rather smooth, but the discoloration to a greenish blue copper corrosion kind of color, and the corroded look of the copper conductor strands there where the outer jacket has pulled back might indicate it's really time to change the battery cable.

Always something of course! But while this is not giving you your low-voltage issue from what I can tell so far, it's not helping anything. And it's just going to get worse.

Paul

 

@1TonBasecamp
Yea, I just jumpered the two red/blue wires together.....and I didn't really expect that to do anything because I have continuity when the clutch is depressed.

I wouldn't know what wires to jump and I don't want to just start jumping wires ***** nilly

I said I was getting 3.5v to the red wire on the starter solenoid.....and I think that should be 12v

I'll check for voltage on the red/blue wires at the connection with the key in the start position and see what I get.

If it's not the clutch switch......or the solenoid.....does that only leave the ignition switch?

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That picture of the starter solenoid......it's not mine LOL.....that was from Mudposrt96.

 

when you turn the key to start position, do you feel a little resistance, and does it spring back to run position when you release the key?
if not, i bet the ignition actuator is broke. easy test. reach up ontop of the column and feel for a small 1/8 rod. while feeling the rod, turn the key from off to run, then to start. if it does not meve between run and start, the actuator in top of the column is broke.

 

One side of the Clutch Interlock switch with the Red/Blue wire should be hot with the key in the Start position. If it isn't then your issue is further upstream, like the Ignition Switch that was previously mentioned. With the key in the Start position full battery power (+12VDC) comes in on one of the Red/Blue wires, if the Clutch Interlock switch is made, then power continues out the other Red/Blue wire to the starter solenoid.

Jumpering the Red/Blue wires together effectively bypasses the Clutch Interlock switch. You verified continuity with your meter, now you are back to power. 3.5 VDC is not enough to energize the starter relay and is most likely not really there. DVMs will lie to you when there are other live circuits nearby. So you are measuring a phantom voltage or something is back feeding the circuit, but not enough current to energize anything.

 

But when you jumpered the two together, did you turn the key to START? That was the point of connecting the two in the first place. As was just said, that action bypassed the interlock switch, so turning the key to START would have resulted in a spinning starter had the interlock switch been the problem.

Certainly. Not a good thing.
But maybe I wasn't clear that you were simply applying 12v directly (from the battery or another hot wire. Or even a battery charger or perhaps even a 9v battery?) to each of the Red w/blue wires in turn.
If you touch 12v to the wire going into the switch it won't hurt anything because that's what it's designed to handle.
If you touch 12v to the wire going out to the starter relay you "should" hear the relay click under the hood.

Correct. You do realize though, that the Red wire (probably with a faded blue stripe) is the same wire that you're messing with at the interlock switch connector?
This is all one circuit, with various controlling devices along it's length. The Red w/blue wires at the switch are the same Red w/blue wire at the relay/solenoid.

That's a good place to restart your quest. If you're not seeing 12v at one of the wires, then as mentioned the problem is before the interlock switch.

Unfortunately no. But it certainly narrows it down.
It can still be wiring and/or connectors. But luckily(?) the most common failure points are switches, not the wiring. Ford and the other OE's do a good job of using quality wire (most of the time) and very high quality connections and splices.
Very reliable, but age can have it's way with anything in the end.

The ignition switch is definitely high up that list though.

Ahh, that would have been good to know so we weren't working under an assumption.
Not a bad thing, since it is a good pic and was probably quicker to hand than going out and taking one of yours. But can you do that when you get a chance anyway please?
It would help I think to know what yours looks like. Might not tell us anything, but then again, it might.

Paul

 

Thanks for the detailed response 1TonBasecamp

Let me work through that checklist and get back with some better answers.

But, right now.....my guess is the switch.

If there is nothing downstream of the clutch switch......and the solenoid is good......it's time to look upstream and the ONLY thing that I know of that is upstream....is the switch.

 

OK....no power to either of the red/blue wires.

I did not realize that was the same wire at the solenoid, but it does make sense.

It's gotta be the switch.....right?

 

Or open wire/bad connection.

 

Wire, connections/splices, switch, etc.
Next step then, in my opinion would be to test the output of the ignition switch.
If you're still young and flexible and don't mind doing your best impression of a human pretzel, pop under the dash and put your voltage probe on the Red w/blue wire's terminal where it comes out of the strain relief/connector on the back of the switch.
With the key in START you should see power.

If you do get full battery voltage (or within half a volt let's say) there is something wrong with the wire between the ignition switch and the interlock switch.
If you don't get power, or find substantially reduced power on the wire at the back of the ignition switch, then (since I believe you already verified that 12v was getting to the switch? I don't remember) then yes, the ignition switch is buggered.

Paul

 

i would still check the ignition actuator before tearing the switch apart. i have replaced 50 actuators for one switch.

 

The actuator moves up and down.....checked that already.....because I have replaced it in the past and I HATE that job.

No voltage at either red/blue wire at the clutch switch

So....when we say "replace the ignition".....I'm assuming that is more than just the key switch?

 

ignition switch, on top of the column roughly above the brake pedal, it is what the rod connects to on the other end from the actuator.

 

Hmmmm, so can a person bypass that switch by jumping the wires to see if that is the issue?

I'll climb under there and see if I can find it.....on top of the column....sheesh.....

 

Just to follow up....

I replaced the ignition switch that is located on top of the steering column (gotta pull some dash bling and drop the steering wheel to get to it)

Pretty easy job really.....and it works perfectly now.

Thanks SO MUCH for all the help