EZGO many things ok but something ain't.

[Old MXer]

First, apologies if this has been covered before. I looked at many posts but didn't find anything that referenced the FR voltage I'm finding.

98 TXT 36V G3698 1101275. Bought it used about five years ago. Had to replace one battery & cable due to a bad connection, otherwise no problems.

Wife was taking the dog for a ride. Things were good until she stopped & tried to back up. It made a slight reverse movement & that was it. Now won't go either direction.

Following diagnostic procedures from this forum, found throttle good, solenoid good, all cable ends good, connections good & tight. Unless it was a obvious reconnection, I labeled or photo'd anything I disconnected.

Took the FR apart & found nothing but normal wear. No signs of high temp damage. Cleaned up the copper smearing, resurfaced the contacts, & shot a little carburetor cleaner on the kruddy places. Added just a hair more spring tension to compensate for contact wear. It didn't fix or change the problem but did satisfy my curiosity about what was inside the thing.

Should the FR shaft be lubed?

So right or wrong, here's where I'm at:
With meter neg lead on Pack neg post, shift in either F or R, ignition on, pedal pushed, I have pack voltage on all FR posts ( A B C D ) at the same time. My guess is, that's probably not good & it's the reason I took the FR switch apart. ( Incidentally, if the pedal isn't pushed, I have about three volts less than pack, still on all posts.)

I could sure use some help with this thing before the wife makes good on her threat to call the dealer to fix it.

Can a bad motor take out a controller?

[Old MXer]

Pack voltage = 38.2

[kgsc]

Check for pack voltage on the red wire going to the top of the controller. Should be live when the pedal is pushed.

[rockfordpi]

Originally Posted by Old MXer

First, apologies if this has been covered before. I looked at many posts but didn't find anything that referenced the FR voltage I'm finding.

98 TXT 36V G3698 1101275. Bought it used about five years ago. Had to replace one battery & cable due to a bad connection, otherwise no problems.

Wife was taking the dog for a ride. Things were good until she stopped & tried to back up. It made a slight reverse movement & that was it. Now won't go either direction.

Following diagnostic procedures from this forum, found throttle good, solenoid good, all cable ends good, connections good & tight. Unless it was a obvious reconnection, I labeled or photo'd anything I disconnected.

Took the FR apart & found nothing but normal wear. No signs of high temp damage. Cleaned up the copper smearing, resurfaced the contacts, & shot a little carburetor cleaner on the kruddy places. Added just a hair more spring tension to compensate for contact wear. It didn't fix or change the problem but did satisfy my curiosity about what was inside the thing.

Should the FR shaft be lubed?

So right or wrong, here's where I'm at:
With meter neg lead on Pack neg post, shift in either F or R, ignition on, pedal pushed, I have pack voltage on all FR posts ( A B C D ) at the same time. My guess is, that's probably not good & it's the reason I took the FR switch apart. ( Incidentally, if the pedal isn't pushed, I have about three volts less than pack, still on all posts.)

I could sure use some help with this thing before the wife makes good on her threat to call the dealer to fix it.

Can a bad motor take out a controller?

Yes, bad motor can damage controller.

It is normal to read pack voltage on all terminals on F/R switch (when reading to main negative) with pedal down.

When Sol Closes, it brings pack voltage to/from the B+ terminal on the controller through the motor armature and fields back to the m- terminal.

The M- terminal is connected inside the controller to the B- terminal (which goes to main battery negative). The controller regulates the amount of voltage that travels between M- and B- in order to control the speed of the cart.

So, if you have pack voltage back at M-, either controller is not getting powered up by the red wire as KGSC mentioned, not getting proper signal from throttle to pass voltage through to B- or Controller is getting power and proper throttle signal and is not responding to signal.

see
http://www.buggiesgonewild.com/attac...on-diagram.jpg

[Old MXer]

thanks for the replies guys. Much appreciated.

KGSC, pack voltage is 38.1 this morning.

Red wire is 37.3 pedal down.

rockfordpi, M- is 38.1 pedal down.

Rechecked throttle at white wire.
At click = .4
Full throttle = 1.7

[Old MXer]

Thanks for the diagram.

Question - It shows a connection from FR C to A2 on the controller. I don't have a lug, just a raised area labeled A2, there on the controller, & only one wire on FR C....?

Is this what is referred to as a three lug controller?

Every series diagram I've seen shows a A2 controller lug.

[rockfordpi]

Originally Posted by Old MXer

Thanks for the diagram.

Question - It shows a connection from FR C to A2 on the controller. I don't have a lug, just a raised area labeled A2, there on the controller, & only one wire on FR C....?

Is this what is referred to as a three lug controller?

Every series diagram I've seen shows a A2 controller lug.

Yes, you have a 3 lug controller, just ignore the A2 on the diagram.

[rockfordpi]

Originally Posted by Old MXer

thanks for the replies guys. Much appreciated.

KGSC, pack voltage is 38.1 this morning.

Red wire is 37.3 pedal down.

rockfordpi, M- is 38.1 pedal down.

Rechecked throttle at white wire.
At click = .4
Full throttle = 1.7

I want to get the real experts to chime in here, but I think if you have 38 volts at M1 and 37.3 on the small red wire to controller, it has to be either throttle signal or bad controller. I can't remember (and not where I can look up) the parameters for proper throttle signal, but obviously something is changing in the throttle signal when throttle is pressed.

So, if you have a good throttle signal, I am thinking you probably have a controller failure. However, there might be a scenario where pack voltage could travel through the motor and back to the controller and there still be an issue within the motor where it would not turn. However, it seems like there would be excessive heat somewhere if that were the case.

There is a way to bypass the controller and bring power straight to the motor to test it. I know one way to do it, but I will let the experts share the easiest and least risky way to do as my way might not be the best way.

Just don't replace the controller though until you get a second opinion from one of the experts here.

[Old MXer]

Least risky sounds good.

Family night movie starting, will check back tomorrow.

[JohnnieB]

If you are getting full battery pack voltage between the controller's B- and M- terminals when pedal is pushed just far enough to make the solenoid click, the voltage doers not decrease to zero as the pedal is pushed to floor and the ITS voltage on the white wire is (Pin-1) is between 0.4V and 0.6V when solenoid first clicks and between 1.5V and 1.7V when pedal is on floor, then the controller is bad.

------------------
Series controller - 101

The "valve" (MOSFETs) that limits the number of amps the motor is allowed to draw is located between B- and M- inside the controller. When the valve is shut off and the high current circuit is intact, the closed valve will be the only open in the circuit and full battery pack voltage will be dropped across it. As the throttle signal tells the valve to open, the battery pack voltage will be dropped proportionally across the motor and the partially opened valve until the valve is fully open and all of the battery pack voltage is being dropped across the motor with none dropped across the fully opened valve.

---------------
F/R switch (Series Type) - 101

When the valve in the controller is shut off, full battery pack voltage will be measured on all four studs of the F/R switch. When the valve in the controller is partially open, the four studs on the F/R will measure less than the battery pack voltage, but not evenly because some other the studs are connected to the armature and the others are connected to the stator. When the valve in the controller is wide open, the four studs on the F/R switch should read very close to 0V.