[foodplot]

Hi, awesome forum; have learned so much from you all, but am boggled with my cart's issue. It may seem long winded and maybe not relevant, but I will share all info I have in the hopes that one of the experts will see what the issue(s) is.

I have a 2003 48v IQ car with Curtis 1510-5201 stock controller and MCOR. Batteries are 6 months old and check out fine. Cart always ran great, and I don't use it very much. I noticed a few weeks ago that after driving around
for about 30 minutes at slow speeds the motor was hot to the touch. Then last week I noticed the cart would run fine but begin to slow down and surge. I read that it could be the speed sensor and to unplug it and see if it made a difference, which it did not. I checked my connections for loseness and the A2 wire at motor was warm so I checked it for tightness. In doing so I hit the wrench across the A2 and F2 terminals on the motor, and it arced. After that is when I noticed the resistor across the solenoid was getting very hot and the cart would not move. I checked the resistor and it is around 500 Ohms. If you let the resistor cool down (removing negative battery lead) and then hook battery back up, you can hear the solenoid engage as you depress the pedal. You can repeat this (cart in neutral) for about a minute until the resistor heats up then something happens and the solenoid won't "click".

After I removed the ground cable from the battery and let the resistor cool down, I reinstalled the ground cable and the cart would drive but only medium speed similar like the original issue. However, now when I put the rocker switch to Reverse, it also goes forward. Never had this issue in the past. The motor also heats up after a minute of driving to at least 100 degrees. If I remove all the leads to the motor, the resistor does not heat up at all. I reinstalled all the motor leads and the solenoid resistor heats back up, so I tried removing just the F2 lead. That stops the heating of the resistor. If i try to drive in forward with the F2 lead off, I hear the solenoid click and then can hear a low "growl" from the motor as if something is spinning, then within a second I hear the solenoid kick out. If I put the cart in reverse, I hear the same growl and something turning inside the motor and it does this for at least 3 seconds, the cart slightly tries to move rearward then the solenoid immediately kicks out. What would be "spinning" inside?

I jacked up one rear tire and with all leads removed from motor I put jumpers between A1 and F1 and A2 and F2. I then applied 8 volts from a battery to the A terminals. The tire rotated backwards at a pretty good speed. I swapped the negative and positive leads and the tire still rotated backwards. I removed all leads/jumpers and I checked for continuity between A1 and A2 and F1 and F2 and all checked good. I did not have continuity between any A to F or to ground. BTW with all leads removed from the motor, I checked them for voltage with cart switch on and in run mode. A1=15v A2=0v F1=33v F2=15v.

I began to run a check on the speed sensor per the 2008 IQ plus Electric Vehicle Maintenance and Service Supplement Chaper 11. Checking the black/white lead on the 3 pin connector produced 50 volts which is within spec. I checked the red lead and that produced 0.7 volts Spec says 15-16 volts and anything below that you should replace the speed controller. But with so many odd things happening at once I don't know if that is a valid test. Other than purchasing another motor or controller what else can I do to start ruling out items? I have another cart but that is a 1999 with series motor and V-glide (not a resistor cart), but from what I read the motor and controller can't be used in my IQ cart. Thanks!