Ac Dc Voltage And Fan Inop, Please Help

[fur_pig]

I recently purchased an 01 280 txt and on my first outing proceeded to boil it over as the fan is inoperative.

If I undo the fan connector and jump 12v and ground to the blue and black wires, the fan will come on.

If I reconnect that connector and jump the yellow and blue wires at the thermo switch the fan will not come on.

The yellow wire coming into the thermostatic switch has varying AC voltage, about 24v at idle. Someone has cut this harness prior to me buying it, likely to eliminate the lights? I found a single yellow wire coming from a block under the steering stem bearing area. Thinking this may be the voltage regulator for 12v AC, (I circled in red on diagram) I spliced this into my yellow wire coming into the thermostatic switch but it still remains 24v + AC and I still can't get the fan to work.

Could anyone please help? I am pulling my hair out.
Thanks so much!!

James

Edited May 18, 2014 by fur_pig

[huski]

Sounds like you need a new fan switch

[fur_pig]

I bypassed the fan switch and it still didn't come on

[ourian]

If you're still getting 24v AC after splicing yellow wire from 12vAC regulator, I'd hazard a guess that regulator isn't working, did you have it grounded when testing voltage, does it require grounding? Also have a look through this thread http://www.trialscentral.com/forums/topic/45659-txt-280-non-pro-voltage-regulator-fan-motor-not-spinning/

Turns out his voltage regulator was U.S.

Edit - What voltage are you getting between black and red/blue wires to fan?

Edited May 18, 2014 by ourian

[dadof2]

Sounds like the regulator is not working. It could be faulty or it may not be earthed. some regulators earth through a wire, some through the body where they are fastened on.

Fan will probably be meant to run on 12 to 15 volts DC.

[copemech]

You stated you have voltage to the thermo switch, which is good but yet seems a bit high if the regulator was working.

In this diagram, the output for the fan is regulated to DC after the thermo switch and the fan motor is a DC motor that will not run otherwise.

Therefore there is a possibility that the regulator has failed, thus causing the rectifier to fail due to overload.

U can replace the rectifier, but if the regulated output is still too high I think the fan will run up too fast and likely take out another rectifier due to overcurrent.

M2C

[fur_pig]

Sorry for the slow reply, work has been crazy.
I got to mess w/it more tonight and found that now any lead coming out of the rectifier is roughly 20v AC at idle up to 70v AC at high rpm.

It also looks like it's gotten hot and slightly distorted. Is there a way to test my regulator or should I just get a new regulator and rectifier?
Is there a cheap alternative to oem parts?

[ourian]

The voltage regulator (transval 415) should push out around 12v AC and the rectifier (leonelli spain) should push out around 12v DC

If your not sure why it's wired up like this - the original lighting circuit can cope with AC current, that's why there is only a voltage regulator in that circuit, but the fan motor requires DC current hence the rectifier to change AC to DC

As for cheap alternatives unless you want Chinese pit bike parts have a look at these

Voltage regulator

Rectifier

These wired up correctly should do the job

Voltage regulator is simply - black to ground, yellow to yellow side of thermo switch.

Rectifier - Alternator AC to blue side of thermo switch, positive (red dot) to red/blue on fan, negative to black on fan, other AC regulator to green ground.

[Bernie the Bolt]

Hi Ourian

I have picked up on this thread regarding the regulator, only in a Beta Techno.

I have tried to follow the link, but there is an error with it, probably because it is four years old. Can you point me in the right direction again.

Many thanks