what happens if you jump terminal 50 to the battery cable positive right at the starter?

here's the latest from this morning
So I grounded the starter directly too the body with a jumper cable.
Same thing, solenoid clicks starter doesn't turn.
Grounded the trans directly to the body, same results.
Hooked the starter up directly to another battery and it spun like a mother.
So I figure it's not getting enough juice from the direct red wire powering the starter as I have

1-eliminated the yellow wire as fault as it is getting 12.4 volts and the solenoid clicks
2-eliminated the ground problem by bypassing the ground cable and grounding the starter directly to the body
3-eliminated the battery not putting out enough juice by buying a new one and having it load tested
4-deduced that the problem must be lack of enough voltage to power the starter at terminal 50


Comments and directions are appreciated
Thanks
Steve

you said the yellow wire (terminal 30) was dropping to .65 volts when cranking, is that still true?

are both battery terminal clean?

is the body ground clean at the battery?

you cleaned both ends of the body to engine ground strap?

the solenoid requires a lot of current to pull in. even though you have 12v at the yellow wire, there can be resistance somewhere reducing available current.

while cranking, measure battery voltage, battery voltage at the starter and voltage at yellow wire. (yellow wire connected to starter)

do you have a car alarm?

Where did you connect the extra battery? To terminal #50? Or to the big red wire? If the big red wire, then the red wire going from the battery to the starter is your problem. There is either a bad connection on one end, or the wire itself has broken - possibly at a bend? Are either ends bent or do you have questionable terminals or connections?

If the problem is at terminal #50, you may have a bad ignition switch.

Steve,

If you think it is the red wire just use some leads and test it.

I think that the jumper cable may not be giving a good ground. You need serious clean, metal to metal contact.

I have been through a similar situation with a couple of electrical gremlins, my clock didn't work, my starter started intermittently crapping out on me, my light switch went crazy. My fuel pump would turn off, etc. After throwing about 100 hours of time and 1000 dollars, I had a bunch of new parts, but still had the same issues.

I had simply checked my grounds and tightened them down, so I had previously eliminated that as an issue.

Then one day I removed a ground strap and scraped off all the gunk and residue , I sanded all contact surfaces down to metal, and all my problems went away, and my car ran smoother.

I listed this as a priority for annual PMCS (Preventive Maintanace Checks and Services).

Car alarm/ disable?

Thanks everyone
Let me try and answer everything. There is no car alarm. The battery is new and all posts and connections are tight.
Wouldn't the grounding from the jumper cable be enough to get the starter engaged if there was enough juice? It is a brand new ignition switch and when it turns the solenoid engages
I hate electrical problems

Can I just jump from the positive side of the battery to the 50 terminal on the starter without doing anything else and shouldn't the starter spin if it is grounded correctly? And would that not prove the problem is with the power from battery to the 50 terminal the problem?

Yes - so which test did you do that got the starter to spin? Connecting directly to terminal #50 on the starter?

The starter switch wiring goes through several connectors that can be bad all the way to the back of the car and if the car has A/C there is a relay that can cause problems.

Work from the rear of the car forward, start at the 14 pin connector under the plastic cover on the driver's side rear engine compartment . Then move on to the the plug behind the heater blower. There are relays on your car to turn off the A/C and heater blowers when the key is in the start position to save power for the solenoid load. The electrical part of the switch can fail, and the mechanical switch can fail separately, then it is time to go for a push button.

I actually jumper directly to the cable coming out of the solenoid (connected to the 50) into the starter motor housing from another battery.
There is no AC/ heat etc in the car.
I am getting 12.4 volts right at the yellow wire on the solenoid with the starter switch on so I don't think there is any reason to suspect the starter switch or wiring back to it. If I didn't get 12.4 volts there I would trace back and find the problem, but since I'm getting 12.4 I figure that is enough to work the solenoid and when I engage the starter directly it spins so I have got to figure it is the power from the battery to the starter

If the starter turns with a separate supply of power, then there is nothing wrong with the starter. It's got to be something wrong with the big red wire going from the battery to the starter. Could it be touching something? Partly melted somewhere? Bad connection at one of the terminals?

is the yellow wire connected to the correct post on the solenoid?

what type of connections do you have at the battery? IE, are they original, are they the type that clamp to the cable? how do the cable ends look? any corrosion on the cable going into the connector?

is the solenoid pulling in with the ignition switch? do you hear a click?

all these tests should be done with the battery that is in the car. this extra battery is confusing. im not sure if the good results are with the extra battery or the one in the car.

whe you say "engage the starter directly" are you jumping from the battery cable over to the yellow wire? and, the car starts as it should? or, are you jumping over to run the starter motor only?

Solenoids are the usual culprit with these types of starting difficulties, exact same thing happened to me with my Expedition, I bench tested the whole unit and found that the solenoid was not triggering the starter. I replaced the starter and the problem was solved.

So I'm pretty sure I found the problem. I powered the starter with a cable from the cars battery. Turned the key and it started.
So I obviously have a problem in the red wire running from the battery to the starter. No to start tracking that down

Post a picture of the positive battery terminal, wire usually goes bad-corrodes-right at the terminal. You can just replace the battery terminal and clean up the wire.

New battery and new cables

^^^ What he said.

They can also be intermittent.

Thanks everyone.
I think I have found the problem. It was two fold.
First there was a lousy connection from the power supply side and now I need to replace the trans ground strap.
Should have it finished tomorrow

I'm back.
Rewired the power supply side. Tested by running cable from starter to ground and the car started right up. Removed what looked like a perfectly good ground strap and cleaned the mounting points. Installed new ground strap. Car started right up. Buttoned everything up, put tires back on dropped car off jacks. Get in ....................................... car wont start. Same problem and same sound as when I got on this merry go round a few days ago.
I hate electrical but this is nuts.
Any idea's why the car would run the two times it was on jacks but would not run as soon as it was off jacks.
I raised the car up from the engine sump plate and supported it by the torsion bar covers
This is driving me nuts as I had plans for some driving this weekend

Thanks
Steve

Explain "rewired the power supply side"
You ran a new wire from the battery to the starter?
Also what cable did you run from starter to ground?

After I replaced the ground strap the car started.
Now it will not, so I ran a jumper cable from the starter to the body ground by the trans. Turned the key and nothing.
So I figured the new ground strap was good.
Then I ran a jumper cable from the battery to the terminal 30 direct. Turned the key and no start.
Then I ran the jumper cable from the battery directly to the field starter winding coming out of the solenoid and the starter spun like it should. This also proves that the ground strap is good because I did not ground the starter any other way
My "assumption" is that it is a bad solenoid, but what confuses me is it started up fine after I replaced the ground strap and it was on jacks.
I know I was getting 12.4 volts at the yellow wire at terminal 50 from the ignition switch when turning the ignition and I know I'm getting and I know I'm getting 12.4 volts to terminal 30 because I ran it direct from the battery so the only thing I can assume is the solenoid is intermittent or bad.
Does anyone know how much draw (amps) the solenoid needs? It can't be a lot as it is only a ten gauge wire