TC40DA cruise control

[gnwillson]

Cruise control did not work when I got tractor. Read all threads that apply to cruise. Have power to magnet ( test light and volt meter ) but will not energize. Checked it with ohm meter it open. Got a new magnet. Still won't energize. Checked new magnet with ohm meter its open. Applied 12 volts to both neither would energize. Help Please

 

[jinman]

Did you check the new magnet before you installed it? There is always a chance it was bad out of the box. I know you must feel "snake bit" by this problem, but you also need to check the voltage coming from your electrical system to see if it is way too high (most likely not or you'd be frying other things and blowing fuses). In addition, you need to load test the circuit to make sure it is not opening under current demand, specifically the cruise relay. I'd use a regular 12-volt light bulb to put a significant load on the circuit. For testing the magnet, if you jumper 12 volts from a battery directly to the magnet and it won't pick up a few nails, then you have two "toasted" magnets. From your post, it sounds like you've done something similar.

I'm getting ready to leave to go out to dinner, but I'll look at my manual in the morning and post back with what you should read as far as the resistance (ohm) value of the magnet. I'm sure sorry you are having such problems.

 

[Caliche]

Maybe more than one problem?
Did you measure the voltage on both sides of the coil? 12 volts on one side and 0 volts on the other?
Do you need to be up to speed before the switch applies power to the coil?
When you were applying 12 volts to the coil was it still in the tractor or on the bench?
Usually coils are low resistance, check your connections?
Just a few thoughts till Jinman gets to you.

 

[gnwillson]

I did not check the new one. Talked to service manager where I bought the part. He said they would take care of it but had to order it. Think I'll take my ohm meter with me. A long time ago an old radiator man told me "Just because it's a NEW thermostat doesn't make it a GOOD one. Thanks for all the help

 

[gnwillson]

Did not check both sides. Thought one side was positive the other ground.
(Are both wires hot?)

Jinman says in doesn't need to to be up to speed to check. Only needs key to be on.

Yes on the tractor first then on the bench. (the new one)

Checked it on magnet side of plug and plugged in.

 

[jinman]

I did not check the new one. Talked to service manager where I bought the part. He said they would take care of it but had to order it. Think I'll take my ohm meter with me. A long time ago an old radiator man told me "Just because it's a NEW thermostat doesn't make it a GOOD one. Thanks for all the help

The Repair Manual says that the magnet coil should have 11 to 12 ohms resistance (Ohms Law would say it pulls about 1 amp.). It also suggests hooking the magnet directly to a 12 volt battery to test it. In my opinion, there is nothing you could have done to the new magnet to damage it. It's a coil of wire meant to take 12 VDC. There is no way you can short it out. Even if the two external wires shorted out, they would be burned outside the magnet body. Hooking it to a battery charger that can produce much higher than 12 volts could burn up the coil, but by hooking it to a normal 12 volt battery it should not be harmed. If it's open, you didn't do it.

 

[gnwillson]

Thanks for your help and advise

Took tractor to the farm. We've had more rain than usual. Weeds about to get away from me. Right leg is a little sore today.

 

[Caliche]

"Did not check both sides. Thought one side was positive the other ground.
(Are both wires hot?)"

You need a complete circuit, if both sides are 12 volts the coil will never energize. Need to measure 12 volts across the two ends of the coil. You could have a broken ground (0 volt) wire.

Jinman, what switches, the 12 volt side or the ground side?

 

[Caliche]

"In my opinion, there is nothing you could have done to the new magnet to damage it. It's a coil of wire meant to take 12 VDC. There is no way you can short it out.

Most electromagnets get very hot and can open if the magnetic circuit is not made. Takes some time though........

 

[jinman]

Jinman, what switches, the 12 volt side or the ground side?

+12 vdc is always switched. Switching ground and leaving one wire hot all the time is a recipe for disaster. Remember that gnwillson said he checked the magnet for continuity and it was open. That fact pretty much trumps all the other checks you could do.