Marathon - Jumps in Gear

[jej3]

Okay. A couple of bizarro things are going on with my 1988 Marathon.

Once I returned home from a 1.5 mile drive and was parking cart in garage, the cart Reverse buzzer went crazy and stayed on regardless if the key was switched and whether the F-N-R was in Forward or Reverse.

I disconnected the battery and the next day thought I disconnected the black wire for the reverse beeper as I thought MAYBE the micro-switch went bad.

Well, I didn't actually disconnect the black wire for the reverse beeper, it was actually the one at the top post on the F-N-R switch.

I reconnected the black wire and the cart was jumping into gear as soon as the cart was turned on. No need to push the pedal in.


I decided to take the F-N-R out and clean every contact I could with DEOXIT (works great for my electrical gremlins on my Porsche 92 and at the same time decided to put the rebuilt speed switch board in. I also bent one of the rollers on one of the two Micro-Switches back into place.

Well, I did all of that, and it still jumped into gear. I don't know if the reverse beep is still there as I did finally disconnect the beeper because it drives me nuts. I tried swapping out solenoids without any luck and the only thing I didn't do was replace anything on the F-N-R switch or the Microswitch on the speed switch board.

What does it sound like to everyone? I'm out of ideas and am trying to keep the cart as a resistor cart as I probably won't keep it more than another year or so.

Any ideas?

[cgtech]

928 nice. So, it seems the pedal microswitch is stuck on, or solenoid is welded. The only switch you messed with was the 2 with rollers on the F&R?

[rlw]

Jej3,

I'm not sure what you mean by "it jumps in gear". Are you saying that the cart moves when you turn on the key without depressing the pedal? Or are you saying that as you press the pedal, the cart acts as if the pedal is all the way down?

If that's the case, do you see any arcing on the accelerator wiper board?

I had a similar problem this summer. It turned out to be one of the cables going back to the resistor assembly. It had gotten so hot that the solder melted out of the lug.

Check the cables to the resistor (pull on 'em!).

As for the beeper, that sounds like a stuck microswitch.

Hope this helps...

RLW

[jej3]

Originally Posted by rlw

Jej3,

I'm not sure what you mean by "it jumps in gear". Are you saying that the cart moves when you turn on the key without depressing the pedal? Or are you saying that as you press the pedal, the cart acts as if the pedal is all the way down?

If that's the case, do you see any arcing on the accelerator wiper board?

I had a similar problem this summer. It turned out to be one of the cables going back to the resistor assembly. It had gotten so hot that the solder melted out of the lug.

Check the cables to the resistor (pull on 'em!).

As for the beeper, that sounds like a stuck microswitch.

Hope this helps...

RLW

Thanks. If I turn on the key, the cart goes in the direction selected on the FNR switch without pressing the accelerator pedal.

I had the problem with the original wiper board installed and I replaced the wiper board with a reconditioned one and I used new 2GA cables from the board to the resistor pack.

I am just wondering if the stuck Microswitches OR something else messed up in the FNR assembly is causing this.

I hate to just replace parts but I have no idea what the issue is....

Thanks for any help!

[jej3]

Minor update....

The Microswitch with the roller that was bent, which I bent back into place was the reverse buzzer. Now I only get reverse beep when the FNR is in reverse, key on or not.

Nothing else to update but clearly that Microswitch is working.

Am I right to think...

the ONLY thing which would control acceleration is the wiper board?
the other Microswitch on the FNR is working as the cart does go in both Forward and Reverse?

If the wiper board checks out, could wiring of the black wire from the Microswitch be suspect?

[jej3]

Major update -

pulled the microswitch from the wiper board and it was clearly not actuating. Measured resistance using Digital Multi-Meter across Normally Closed and Common terminals.

It was reading 1 when closed, 0 when opened. So switch was working.

Bent the roller slightly to ensure it is actuated.

I would NOT advise replacing a microswitch without taking out the wiper assembly BUT it got it buttoned up enough to test it and no more surging when the key is switched on :)

[rlw]

Jej3,

You mentioned that you replaced the original wiper board with a rebuilt one. To get the solenoid to activate, you have to have the key in the "ON" position, the FNR switch in F or R (and the associated microswitch "ON"), and the pedal partially depressed (and closing the microswitch on the wiper board).

Having all three ON (key, FNR in F or R, pedal depressed) actuates the solenoid. That's just the first part of making the cart move.

The second part is that there has to be a high current circuit to the motor. That happens when you slightly depress the pedal. The wiper arm contact slides off the bottom position contact (disconnected from ANYTHING) on the wiper board and slides onto the second contact. That is wired up through the resistor, then to the motor. THEN, the motor spins and the cart moves. As the wiper arm contact hits each successive contact, you're basically bypassing more of the resistor and sending more juice to the motor. When the pedal's floored, you're sending ALL the juice to the motor.

If there's a short between the bottom contact and the second one, what's happening makes sense.

If the accelerator linkage is bent, that could pull the wiper contact onto the second contact without pressing the pedal.

Remove either the positive or negative cable from the battery pack (those posts also have cables that go to the charger socket), so the cart won't move while you're looking at things. Also, it's a good idea to put the rear end up on jackstands in case something goes wrong.

While it's up in the air, take a look at the accelerator linkage and make sure it's not bent anywhere.

Take a look at the position of the wiper arm while the pedal's NOT depressed. The wiper contact should be resting fully on the bottom, disconnected, fixed contact. Any chance that the moving contact is touching the second-from-the-bottom fixed contact?

Have someone press the pedal while you watch the wiper arm move. Make sure that when your helper releases the pedal, it's all the way back to the disconnected contact.

If all that fails to find the problem, you'll need to pull out the wiper board and carefully inspect the eeeeeency-tiny-weeeny gap between the contacts - make sure there's nothing in between the bottom and second contact that could be shorting them together. You could even throw an ohmmeter between the first and second contact - it should read wide open.

Cgtech's suggestions in the second post make alot of sense - along with having a short circuit between the bottom contact on the wiper board and the second one up. The bottom contact isn't connected to anything, it's just a place for the wiper contact to rest when the pedal isn't depressed. The gap between the contacts is very small - arcing could create a short in that gap by melting a little bit of copper.

The other possibility is that DEOXIT is conductive, and you have some of that shorting the bottom contact on the wiper board.

Short of me crawling under your cart, that's about all I can think of.

JohnnieB might jump in here - he's always good for a wiring diagram with the pertinent circuits highlighted.

Good luck, and let us know what you find.

RLW

[rlw]

Jej3,

Sorry, somehow, I skipped your last post, didn't realize you got it working (WHAT you did to get it working doesn't make sense to me, but, HEY! It's WORKING!)

Glad to hear it's fixed!

RLW

[jej3]

Thanks, RLW. I appreciate the thorough explanation! I'll clarify what I did...

I installed the new wiper board with a new microswitch and likely didn't have the microswitch being properly actuated by the "wiper" arm pedal linkage on the wiper board or put differently, it was stuck open as if the pedal had been pressed.

I also think this made for some "minimal" amount of alignment issue on the wiper board contacts where the bottom contact and the second contact were being touched.

All I know is before I removed the Microswitch from the wiper board, I was getting 36+ volt on both the Common and Normally Closed contacts.

I removed the Microswitch from the wiper board and it wasn't great at actuating. I tested for continuity across the contacts and found it not to be actuating.

I bent the roller assembly down slightly (maybe 1/8 to 1/4") and it actuated better (clicked). Repeated continuity test, and continuity broke when the switch actuated (opened).

I also TWEAKED the Microswitch for Reverse Beeper more significantly as one of my kids must have really thrown the handle on the FNR switch (or I did it after my late night run home from an Oyster Roast :) ) by bending the roller back into place on the Reverse beeper Microswitch.

I don't know how a stuck Microswitch for reverse beeper would play into this but I suspect everything is possible.

I at least now understand most elements of the Marathon's battery and acceleration circuits :)