TR2/3/3A tr3 original solenoid

A while back Geo post something from the Jaguar guys on fixing an original solenoid, but I have trouble finding links; does anyone have that handy, or some more information?

Your memory is better than mine, I had quite forgotten and had to do a search to find it...

https://www.britishcarforum.com/bcf...-Starter-Solenoid-Question&highlight=solenoid

The direct link: https://www.jag-lovers.org/snaps/snap_view.php3?id=1458846628

Thanks Geo that is what I was looking for. If Freud where here he would know, I was looking for anything to break from body work. However, I did purchase a solenoid on EBay and it did not work, and that is my story and I am sticking to it!

Maybe someone can help me with the first picture on repairing the solenoid. I am guessing that with the mutimeter he is checking to see there is no short between the small wire from the key and ground, but I just want to be sure because the article suggests checking the magnetic field. I guess they are the same.

Well the article says very little, but I can guess what it was trying to say with that picture(s). The solenoid is a type of relay. The (key) small wire is used to activate it. I assume they are using an ohm meter to measure a low resistance between the small wire and the case. Alternately, they might be providing +12v across the small wire to the case. When powered, you should hear it click, and see the button move slightly inward. The author believes you are working on an old unit that may have stopped working due to pitting and carbon build-up inside the sealed unit. He is not thinking you are working on a brand new, out of the box failed unit. So to answer your question, the coil should (electrically) look much like a short between the start-wire and the case. (The internal coil is just a winding of wire between start terminal and case.)

When energized, the other two larger posts should also look like they are shorted -the same as if you were to press the button to short the two large terminals/energize the starter.

Or...he means if it clicks but doesn’t pass any juice.

The cool thing about solenoids is the contacts tend to be self cleaning, meaning as long as you use them frequently they maintain good contact.

Well that is my dilemma because in my way thinking with no power the ohm meter should look like an open circuit hooked across ground and the small wire.

If power were applied, then I could see all connections except ground showing short.

It is the magnetic reference that really has me confused. But yeh relays are coils and I guess magnets.

So in yes or no terms if I have no power and hook an ohm meter where he has it I should read open/infinity –yes or no?

Plus how does the ground come into play?

It would read about 8-12ohms (The resistance of the internal solenoid coil).

Ground always plays a role. Ground is the return path for the current to flow from the battery, to the switch in start position, to the small lug on the solenoid, thru the coil, and into ground, which completes the ground path, since the battery (ground) is also connected to ground. Without ground (the return path), no electricity flows.

So, you will not see an open on the coil, unless the coil wire is broken. It should look more like a short (to it's housing/ground).

The key switch is only providing a current path for the small amount of current needed to energize the solenoid coil. When the coil is energized, it will push or pull the internal copper disc into contact with the other two terminals (one to the battery, one to the starter motor). Then the large amount of current needed to run the starter will pass thru the copper disc and terminals completing the path for the starter motor.

Ok guys that makes sense. For a moment right after I wrote that, I realized I was thinking of AC current, like a hot water tank and how they do not need a ground, the oscillating current and pex pipe stuff. I remember when my father was living and he saw there was no metal cold water pipe for ground on a hot water heater; it confounded him. Plus I guess the second ground wire would be insurance for the case ground.

Now it is Back to body work were I can get Buddisticaly cool and sand and not think and let my hatred for evil Bay go.

OK, I stand corrected... Let me rephrase: On a single phase, or DC system, ground always plays a role.
On a multi-phase A/C system, ground may not be involved. A home water heater utilizes two out of phase 110v AC lines for the 220v differential to run the heating elements, and the ground isn't necessarily involved in the flow of electricity. Either 'leg' of the supply will measure 110v with respect to ground, but will measure 220v with respect to each other. The supply is from a center tapped transformer, with the center grounded. Our cars are mostly DC systems.

Now you may return your religious endeavors.