1994 Medalist, ITS Issue I need help with

[rustyself]

Thought controller was bad, so replaced it and solenoid with new.
Voltage remains at pack voltage on b- and m- with full pedal press.
Red wire at controller - pack voltage
White wire is within spec, .5-1.6 volts

Black wire at controller AND at ITS sensor is 13.77 volts. Herein lies my question, I have read voltage should be 14.4, and I've read voltage should be 9-11.5 volts. When I disconnect the plug at controller, there's no voltage on black wire, or controller pin. I'm not sure which side I should be reading voltage, though- the unplugged connector end, or at the controller pin.
The cart won't move in either direction. If I jump b- and m-, it goes wide open ( with throttle ms made).
Any input would be helpful, thanks in advance.

[rustyself]

Forgot to mention- 36v series motor. Thanks again y'all.

[JohnnieB]

For a 94 Medalist with a Curtis 1206 controller, the white wire should have from o.43V to 0.53V when pedal is pushed just far enough to make solenoid click and go to 1.5V or above when pedal is on floor. The black wire is supposed to be above 14V and less than 15V.

The voltage on your black wire is a bit under specs, but the white wire voltages are within specs and you've got pack voltage on the red wire in the molex plug, so the voltage between M- and B- ought to decrease when pedal is pushed.

The circuit that controls the amount of amps passed to the motor is located between B- and M- so when you jump between them your are bypassing the speed controller and applying full battery pack voltage to the motor when solenoid contacts are closed by the pedal switch.

Your controller is being told to run the motor, but isn't doing what it is being told to do, so the controller is bad.

[rustyself]

Originally Posted by JohnnieB

For a 94 Medalist with a Curtis 1206 controller, the white wire should have from o.43V to 0.53V when pedal is pushed just far enough to make solenoid click and go to 1.5V or above when pedal is on floor. The black wire is supposed to be above 14V and less than 15V.

The voltage on your black wire is a bit under specs, but the white wire voltages are within specs and you've got pack voltage on the red wire in the molex plug, so the voltage between M- and B- ought to decrease when pedal is pushed.

The circuit that controls the amount of amps passed to the motor is located between B- and M- so when you jump between them your are bypassing the speed controller and applying full battery pack voltage to the motor when solenoid contacts are closed by the pedal switch.

Your controller is being told to run the motor, but isn't doing what it is being told to do, so the controller is bad.

Thanks for the insight. That does leave me with questioning how two new controllers could be bad back to back, though. One was a reman, and this latest one is new.
Should there not be voltage either on the controller pin or the connector on the black wire when unplugged, though? I'm confused about where that should be measured, but in any case, it is 0 volts on the connector side and the controller pin side, when unplugged.

[JohnnieB]

Originally Posted by rustyself

Thanks for the insight.
1. That does leave me with questioning how two new controllers could be bad back to back, though. One was a reman, and this latest one is new.

2. Should there not be voltage either on the controller pin or the connector on the black wire when unplugged, though? I'm confused about where that should be measured, but in any case, it is 0 volts on the connector side and the controller pin side, when unplugged.

1. Two bad controllers is unlikely, but it does happen more often than it ought to.

2. If only the black wire is unplugged. If the 5-pin molex connector is unplugged the controller isn't powered up, so there would be no voltage on the controller's pin for the black wire.

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Does your cart have a Curtis 1206 or a Curtis 1204 controller? (The more common 1206 has a 5-pin molex on top and the 1204 has four individual spade connectors.)

I've been working on the assumption you have a 1206 since nearly all Medalists with series drives have it. The carts with a 1204 are a slightly different animal.

[rustyself]

Originally Posted by JohnnieB

1. Two bad controllers is unlikely, but it does happen more often than it ought to.

2. If only the black wire is unplugged. If the 5-pin molex connector is unplugged the controller isn't powered up, so there would be no voltage on the controller's pin for the black wire.

-----------------
Does your cart have a Curtis 1206 or a Curtis 1204 controller? (The more common 1206 has a 5-pin molex on top and the 1204 has four individual spade connectors.)

I've been working on the assumption you have a 1206 since nearly all Medalists with series drives have it. The carts with a 1204 are a slightly different animal.

It's a 1206 five pin.
That makes sense, the red wire, I'm guessing, turns on the controls.
I read in the manual that my black lead going to the ITS should be 9-11.5 volts when included in the inductor loop. My guess is this wire feeds voltage to the loop, and the white wire is the resulting voltage from passing it thru the inductor, which in turns tells the gates when/how much chopped-up DC to send to the motor high current output negative m- lead.
I found another anomoly which may be related to the higher than normal black ITS lead- when the cart is in FWD, the white wire has ~.45 volts even with the pedal in full up position and the solenoid not closed.
Reckon what's causing that?
It does this with both controllers, which I am swapping to look at references.

[JohnnieB]

The ITS throttle circuit has three parts, 1. the power source in the controller, 2. the ITS sensor in the pedal box and 3. the throttle position detector in the controller.

The ITS sensor is a proximity detector (Schematic attached) and the more ferrous metal in proximity of its coil, the more amps it draws.

EZGO (Curtis) feeds it with a constant voltage source and the voltage at the position detector increases as the pedal is pushed down. On the other hand, Alltrax feeds it with a constant current source and the voltage at the position detector decreases as the pedal is pushed down. (Probably to avoid paying royalties - it is a patented device)

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That phantom voltage might be cross-talk at the in-line connector to the pedal box. The green and red wires to the pedal switch have battery pack voltage on them.

Trace the gray cable from the pedal box through the cart's frame and you'll eventually find a 4-pin in-line connector. Cut the connector off and replace with individual butt-splices covered with marine grade shrink tubing (water proof) or solder the wires and shrink tube.

[rustyself]

Originally Posted by JohnnieB

The ITS throttle circuit has three parts, 1. the power source in the controller, 2. the ITS sensor in the pedal box and 3. the throttle position detector in the controller.

The ITS sensor is a proximity detector (Schematic attached) and the more ferrous metal in proximity of its coil, the more amps it draws.

EZGO (Curtis) feeds it with a constant voltage source and the voltage at the position detector increases as the pedal is pushed down. On the other hand, Alltrax feeds it with a constant current source and the voltage at the position detector decreases as the pedal is pushed down. (Probably to avoid paying royalties - it is a patented device)

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That phantom voltage might be cross-talk at the in-line connector to the pedal box. The green and red wires to the pedal switch have battery pack voltage on them.

Trace the gray cable from the pedal box through the cart's frame and you'll eventually find a 4-pin in-line connector. Cut the connector off and replace with individual butt-splices covered with marine grade shrink tubing (water proof) or solder the wires and shrink tube.

That connector was bothering me last night, so I went out to the cart shed (my cart stays at the golf course), took my Weller pen, and flowed and shrink wrapped the wires together.
It was in BAD SHAPE. To the point that most of the connector was melted. Figure it has been fairly loose for awhile.
I plan to play a few times over the next week, so I will report back if it is fixed.
It did begin working again last night.

[JohnnieB]

Originally Posted by rustyself

That connector was bothering me last night, so I went out to the cart shed (my cart stays at the golf course), took my Weller pen, and flowed and shrink wrapped the wires together.
It was in BAD SHAPE. To the point that most of the connector was melted. Figure it has been fairly loose for awhile.
I plan to play a few times over the next week, so I will report back if it is fixed.
It did begin working again last night.

Did the mysterious 0.45V disappear after eliminating the in-line connector?

[rustyself]

Originally Posted by JohnnieB

Did the mysterious 0.45V disappear after eliminating the in-line connector?

You know, it was late, and I didn't check.