Reset circuit breaker question (heater)

[David*BJ70]

Hope here is the good place for this question.

Almost all the time, when I use my heater at MAX, the heater reset circuit breaker (driver panel) cut the power off.

This is a good thing... it work ! But I'm tired to always reset it. One option is the set the heater in a lower speed... but sometime I need it at MAX... when it cold or it rain for example.

I figure there is a problem some where... but where.

Someone can give me some tips where to start the investigation.

Is a circuit breaker is good or bad only... or it can be just... worn.

 

[brownbear]

Hey David,

Circuit breaker in a vehicle? Not a fuse?

Yes circuit breakers can get worn. But also maybe it is the wrong size.

Also the motor(blower motor) could be drawing too many amps. It could be tired too.

So you need to know what size of wire is used, what amp draw the blower motor is supposed to be and then pick the circuit breaker size a bit above, but below the melting point of the wires.

I could look at my wiring diagram for the Bj70 when I get home. See what size of fuse is normally in there.

Electric motors that are ready to fail draw more amps, and also work very poorly on lower settings. This making you have to use the higher fan setting.

Hope that helps....

 

[David*BJ70]

Circuit breaker in a vehicle? Not a fuse?

Yes, circuit breaker... like show at page BE-4 of the Landcruiser 10/84 thru 01/90 rapair manual

Also the motor(blower motor) could be drawing too many amps. It could be tired too.

Electric motors that are ready to fail draw more amps, and also work very poorly on lower settings. This making you have to use the higher fan setting.

Is a heater electric motor can be rebuilt by a little motor electric shop ?

Hope that helps....

Thank brownbear... yes, that help !

 

[UpsideDown]

Yes, these circuit breakers do wear out. They are based on a metal strip and once it has flexed a number of times it will cut out much more easily.

It sounds like you need to test the load the motor is placing on the circuit and repair things if the load is too high. Check that the motor spins freely and that the bushings are lubricated with light oil. If the brushes are worn, it could lead to this condition.

If the load is within spec, then replace the circuit breaker. They are used in many different Toyota models (though some may be hidden behind kick panels) and can be had for almost nothing at most wrecking yards.

~John

 

[brownbear]

Yes, circuit breaker... like show at page BE-4 of the Landcruiser 10/84 thru 01/90 rapair manual



Is a heater electric motor can be rebuilt by a little motor electric shop ?



Thank brownbear... yes, that help !

you might be able to rebuild it yourself. If you could source the brushes then it might not be out of the truck too long. Otherwise I would pull it out and take it to an electrical shop to buy the parts. Or maybe they can rebuild it for you.

I'm sure it can be rebuilt at an electrical motor rebuild place. In Montreal there must be that exact kinda place.

But do you have a amp meter(multimeter) with either a clamp on meter or way of checking the amp draw??

pull the circuit breaker out, it should be stiff to pull out. not easy. I would try replacing it with the same size as the manual first. If that keeps popping then then you know its the motor drawing more than the cicuit is supposed to.

How well does the motor run on low setting? The worn out blower motors I have seen didn't run much at low. They barely put out any air and needed to be on full to get enought flow.

Might just take some new brushes and a cleaning, be good for another 200,000 kms.

 

[David*BJ70]

How well does the motor run on low setting? The worn out blower motors I have seen didn't run much at low. They barely put out any air and needed to be on full to get enought flow.

How well ?.. not so well !

In fact, it run at MAX and the speed before MAX. I suspect the blower resistor but I can live with that. (I don't tell you the heater CAN run at MAX.. but for about 10 minutes maximum). I can also live with my actual problem. But my wife always forget it and the reset circuit breaker always turn it off !

Thank you all. I will check the heater motor, then buy a new resistor.... and (first) repeat (again) for the education of my wife !!!

 

[brownbear]

Well ther reistor might not be the problem, as it is used in low fan settings, not high right? it used the resistor to knock down the voltage going to the blower motor. It is a voltage drop device. And it easy to test. It will have a specified resistance it should be. You ring it out with a meter to see.

Other problem could be in the motor windings, they could have a short to ground, the draw is too high and knocks out the c/b.

Ideally you do not want to keep reseting a c/b. On aircraft we are allowed only a couple resets and then it has to be inspected. The don't want a pilot reseting in the air too much, or a fire could happen.