2012 precedent no go pre charge resistor hot

[mgray70]

Working on a 2012 precedent that was intermittent not running, now not running at all. No click. I opened up the controller compartment and could smell something hot, even in tow mode. After checking everything over I noticed the pre charge resistor was extremely hot. I want to think the solenoid is the problem, but the resistor is hot even in tow and even when the go pedal hasn't been pressed for a while. Also I tested the tow run switch and it has continuity in tow and run, so I'm pretty sure it's bad. Any thoughts on why the resistor is hot all the time? Or why it's not running?

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[TahoeDawgZ71]

Pre-Charge resistor is hot because there is a load in the circuit beyond the solenoid. Generally when the solenoid clicks, power will pass through the contacts on the solenoid and into the controller. When the controller is at rest, the solenoid will open (disengage) and allow minimal power to go "around" the solenoid and keep the capacitors within the controller charged. This is the job of the pre-charge resistor. When the controller fails, it often creates a draw far more than the pre-charge resistor can provide, therefore it gets hot. 99% of the time this issue is a failed controller. Replace the controller and the pre-charge resistor and your problem will go away. The same symptoms can also be caused by a short in the electric motor, although this is much less common. The motor can be checked for a short with a multimeter. If the motor passes the test, the controller is definitely your issue. To do a continuity test on the motor, disconnect all four wires from it, and check continuity between A1 and A2. You should hear a beep on your meter and show close to zero resistance. Do it again between F1 and F2, you should have the same results. If you have continuity between either "A" post to either "F" post or to the case of the motor, the motor has a short internally. What's the serial number for the cart you're working on? Need to know if it's an IQ or an Excel cart. Not that it matters for diagnostic purposes, but I've got a few take-off Excel controllers on the shelf with no issues. May be able to help you get back on the road again.

[mgray70]

Originally Posted by TahoeDawgZ71

Pre-Charge resistor is hot because there is a load in the circuit beyond the solenoid. Generally when the solenoid clicks, power will pass through the contacts on the solenoid and into the controller. When the controller is at rest, the solenoid will open (disengage) and allow minimal power to go "around" the solenoid and keep the capacitors within the controller charged. This is the job of the pre-charge resistor. When the controller fails, it often creates a draw far more than the pre-charge resistor can provide, therefore it gets hot. 99% of the time this issue is a failed controller. Replace the controller and the pre-charge resistor and your problem will go away. The same symptoms can also be caused by a short in the electric motor, although this is much less common. The motor can be checked for a short with a multimeter. If the motor passes the test, the controller is definitely your issue. To do a continuity test on the motor, disconnect all four wires from it, and check continuity between A1 and A2. You should hear a beep on your meter and show close to zero resistance. Do it again between F1 and F2, you should have the same results. If you have continuity between either "A" post to either "F" post or to the case of the motor, the motor has a short internally. What's the serial number for the cart you're working on? Need to know if it's an IQ or an Excel cart. Not that it matters for diagnostic purposes, but I've got a few take-off Excel controllers on the shelf with no issues. May be able to help you get back on the road again.

This is what I have. I may be interested if you have have something that will get it back going. Thanks Tahoe!

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[TahoeDawgZ71]

I have exactly what you need. Call me. 706-836-7210. I'm still up.

[mgray70]

I just want emphasize to everyone on BGW to please support our sponsors, especially David and Scotty! Not many big eBay stores or online stores will give you their personal numbers and give you advice late at night or talk with you while at a child's ballgame. I've purchased some things from both guys, and will definitely purchase again. Tahoedawg has offered a good deal on a controller to get this issue fixed. Thanks again for the help Tahoe!

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[Nsane]

Yep, I agree with you, we have some of the best guys on here! David has great service and prices as the others do too!

[TahoeDawgZ71]

Originally Posted by mgray70

I just want emphasize to everyone on BGW to please support our sponsors, especially David and Scotty! Not many big eBay stores or online stores will give you their personal numbers and give you advice late at night or talk with you while at a child's ballgame. I've purchased some things from both guys, and will definitely purchase again. Tahoedawg has offered a good deal on a controller to get this issue fixed. Thanks again for the help Tahoe!

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Your order has been boxed for shipment and ready for pickup. Thank you sir!

[mgray70]

Originally Posted by TahoeDawgZ71

Your order has been boxed for shipment and ready for pickup. Thank you sir!

David, I got the OBC in the other day and got it installed, the cart ran fine. The owner came and got it, took it home said he went about 50 feet and stopped. He said he cycled the tow run switch and it started again. He loaded it up and brought it back to me. That was Friday, I drove it Friday afternoon, and most of the day Saturday before I could get it to do it again. The solenoid would click when the pedal was pressed, but no go then the solenoid would drop out afterwards. Finally got it going again and its running fine now. Any suggestions? We've replaced the control and OBC so far. What's next MCOR?

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[TahoeDawgZ71]

Originally Posted by mgray70

David, I got the OBC in the other day and got it installed, the cart ran fine. The owner came and got it, took it home said he went about 50 feet and stopped. He said he cycled the tow run switch and it started again. He loaded it up and brought it back to me. That was Friday, I drove it Friday afternoon, and most of the day Saturday before I could get it to do it again. The solenoid would click when the pedal was pressed, but no go then the solenoid would drop out afterwards. Finally got it going again and its running fine now. Any suggestions? We've replaced the control and OBC so far. What's next MCOR?

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Do you have a scanner you can plug into the controller?


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[mgray70]

Originally Posted by TahoeDawgZ71

Do you have a scanner you can plug into the controller?


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No, not yet, but thinking about getting one.


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