Belt for 48" deck

[ldabe]

Now I am completely confused as to what is going on with my electrical for the oil cooler fan.

I take my multimeter and test the voltage with the key on at the wires where I cut the original fan off.

12.29 volts.

I test the jumper cables coming from my car and get

12.30 volts.

I start the PT up and check the voltage again,

14.19 volts.

I try both fans by touching the wires and neither fan turns!!!

Hey guys, what the heck am I missing here?

I don't get this at all :-(

Does anyone have a suggestion?
Has anyone ever run into a situation like this before?

 

[ldabe]

Don't you hate intermitten problems!
David from jax

YES!
But this is really not intermitten, it is more of a mystery...at least to me.

There is no intermittent with the multimeter.

 

[BobRip]

The following relates to my PT422, year 2000. Your machine may differ. What is the voltage at the fan with the fan connected? I suspect close to zero. You probably have a leakage path through the failed component which only shows up with no load..

I have had the thermal switch fail and the fuse holder. The thermal switch is located just behind the driver on his left, in the engine compartment. It is mounted on a block of metal which has the transmission oil going through. You realize that the oil has to be hot to turn the fan on. With the fan connected to the PT and key on, check the voltage drop across the thermal switch (also called thermal relay). If it is 12 volts or so it is either not on (too cold, turns on at 135 F, I believe) or defective. Jumper across it and see if the fan starts.

Also check the fan fuse holder. It is located near the thermal switch. I had it fail where the wire going into it connects to one of the terminals. It is a displaced insulation connector, (also given the name by me of "Devil Connector) which in my book should never be used anywhere, much less where there is vibration. Jumper around the fuse with a fused wire and see if the fan starts.

There is another fuse off of the starter which powers everything but the starter. That has also failed, but it shut down the engine, since it also feeds the fuel solenoid. I hope this helps.

 

[J_J]

YES!
But this is really not intermitten, it is more of a mystery...at least to me.

There is no intermittent with the multimeter.

Is it possible that this new fan can only run in one direction, switch the leads and see if it will run. What is the voltage at the fan with the new fan hooked up ? I have seen fans with different part numbers, looked like the same fan, but one of them turns opposite the other. I always thought that if you reversed the leads on a DC motor, the fan direction would change. What if there is a diode in one lead to prevent it from reversing. A diode is used to prevent current from running in a certain direction. Just a thought.

 

[Clarke]

To reverse the new fan remove the clip that holds the blade remove blade turn it over and install clip. Reverse wiring. You may want to put a jumper across the fan thermal switch to check if it is open also check fuse and wiring and make sure you have a good electrical ground on the - side.

sg

 

[ldabe]

I guess I am not saying something right, because from some of the replys I thought I covered those things.

The "Thermal relay" is bypassed. (It's connectors are plugged directly into one another...so the relay has been bypassed)

The "fuse" right after the Thermal relay has been checked and is good.

The wires coming out of the hood have been cut away from the original fan, and the voltage at that point reads
12. 29 volts engine not running.
14.19 volts with engine running.

The new fan connected to the PT does not operate (remember the Thermal relay is bypassed, and the fuse is good)
but, when connected to the battery on my car
it does operate!

The old fan does the EXACT same thing as the new one (which shows the old fan was not bad).

I hope this clarifies the situation better.

This seemed like to me a easy situation to trouble shoot...
but I am completely confused as to why the fan(s) will operate connected to my car battery...
but not to the PT
when the voltage shows that it should.

 

[BobRip]

Fuse can be good, but fuse holder can still be bad. Is your voltage check with the fan connected?

 

[ponytug]

Dear Idabe,

You are doing a great trouble shooting job. Your measured voltages are all look good to me. 12.3V is a well charged lead-acid battery, and 14.19V is a reasonable alternator output.

So,...

The fans clearly work hooked up to a battery. To address the concerns about whether they work both ways is easy to test with your jumper cables, by switch + for -, but I am not sure that it helps you. You can sort out push/pull later.

I don't know how your fan is grounded, but make sure that check the ground part of the circuit. (Start at the battery, clean the ground terminal, check the cable, check the attachment to the tractor. Then check the fan ground, by unscrewing it and putting it back on again, checking the crimp for strength and integrity.)

I would make yourself a test lead, with a 15' of 12ga wire, and an inline fuse holder (with a 20A fuse in it, please!), with one end a spade connector, or soldered into a point, and the other a clip conector (I like to use an aligator clip, but YMMV). Then we'll take a walk through the circuits. You'll have the fan connected to one end of the wire, and then use the pointy end to test the circuit, starting at the battery and then moving piece by piece closer to the fan. Often connections can test good under no load, i.e. with a voltmeter, but not function well under load. The reason to connect your test lead to the fan, is that the wire you are waving in the breeze is unpowered, which is a lot safer than waving around a wire with 12.3V from your battery.

CAUTION: You will be working around a battery that has an enormous amount of energy; lethal amounts in fact. If you have insulating gloves, I recommend wearing them, and stay away from the battery as best you can. We want you to continue to contribute here!

Connect one end of your test lead to the fan's + wire, and leave it there for the rest of the testing.

1) Test the fan by connecting (touching) the spade connector to the + terminal on the battery.

Check to see if the fan turns, it should.​

2) Connect the spade connector to the input (hot(+)) side of the thermal relay.

Check to see if the fan turns, it should.​

3) Jumper the thermal switch. I like to use a stiff piece of solid wire, with just the ends stripped pushed into the crimps if there is room.

Check to see if the fan turns, it should.​

4) Test the downstream side of the jumpered thermal switch by touching the spade connector to the metal part of the crimp.

Check to see if the fan turns, it should.​

5) Check the hot side of the fuse holder, without the fuse in it.

Check to see if the fan turns, it should.​

6) Test the down stream side of the fuse holder with the fuse in it. (I would replace the fuse, if you haven't already. ATM type fuses can often have almost invisible cracks that keep them from working.)

Check to see if the fan turns, it should.​

7) The only thing left from here, is the wiring, but if it also runs the fan, you have an intermittant connection.

Most intermittant connections are failures at the crimps-
Especially, if you haven't been blowing fuses.
Generally, if I have to recrimp connections on rough duty equipment, I follow the belt and suspenders rule. I solder the wire, crimp it, and flow extra solder into the connector post crimping. Try not to let the solder wick too far back up the wire, or it will become stiff and brittle. Delcity sells some nice connectors that have heat melt adhesive in them that will flow over the wire insulation and form a secure, and water/dust tight connection.

I hope this helps,

Peter

I guess I am not saying something right, because from some of the replys I thought I covered those things.

The "Thermal relay" is bypassed. (It's connectors are plugged directly into one another...so the relay has been bypassed)

The "fuse" right after the Thermal relay has been checked and is good.

The wires coming out of the hood have been cut away from the original fan, and the voltage at that point reads
12. 29 volts engine not running.
14.19 volts with engine running.

The new fan connected to the PT does not operate (remember the Thermal relay is bypassed, and the fuse is good)
but, when connected to the battery on my car
it does operate!

The old fan does the EXACT same thing as the new one (which shows the old fan was not bad).

I hope this clarifies the situation better.

This seemed like to me a easy situation to trouble shoot...
but I am completely confused as to why the fan(s) will operate connected to my car battery...
but not to the PT
when the voltage shows that it should.

 

[woodlandfarms]

Electrical gremlins... Hmmmm...

First, voltage change with engine on and off is correct. Alternators put out around 14 volts or so...

There could (probably not) be an amperage issue. Meaning your feed wire has some sort of resistance in it that reduces the amps... That would be a huge longshot.

It could be a bunch of different things. First, Does the fan work on the PT battery directly connected (both ground and hot).

If so we go to B.... Is the ground you are using to test the 12volts at the end of the hot lead the same place you ground the fan and the same way?

Generally there are two reasons for this kind of failure. Bad ground, bad wire. Maybe you are shaking the wire when you connect the volt meter and allowing a connection (or you are getting a good connection with the meter and not with the fan wire). There could be a crack in the 12 volt source wire, or resistance has built up inside the wire. You said the thermal switch has been bypassed. Anytime you create a connection you create a weak link. Fresh, unspliced wire would alleviate those issues.

Finally ground point may be an issue. Lots of PT owners are adding a ground strap from the battery, to the engine, to the frame rail. PT seems to have left a frame rail strap off.

There is no cut and dried reason for electrical issues. You just have to start at the beginning (the battery or alternator) and work your way to the ignition switch, then back to the fan...

If you do replace wiring, use high quality AUTOMOTIVE wire. Automotive is usually more UV and chemical and heat tolerant than home...

Carl

 

[ponytug]

I agree with Carl's comments.

I usually get wire from Del City or West Marine- both sell marine wire, which has been silvered internally, making it more resistant to corrosion. They also use AWG wire gauge, which is 6-12% larger than SAE wire, for less heating, more delivered power. It goes on sale regularly at Del city.

For rewiring, here is a useful set of charts. Don't forget to include the length of the ground portion of the circuit.
Wiring Chart

All the best,

Peter

Electrical gremlins... Hmmmm...

....If you do replace wiring, use high quality AUTOMOTIVE wire. Automotive is usually more UV and chemical and heat tolerant than home...

Carl