Wildman's TJ is getting a face lift

How close is that break to the compressor? Could the failure be heat related?

All the way on the other side of the engine compartment. York is on the passenger front and this is on the driver rear. Why it's only the ARB hose and not the Main or AiRock hose I don't know.
 
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All the way on the other side of the engine compartment. York is on the passenger front and this is on the driver rear. Why it's only the ARB hose and not the Main or AiRock hose I don't know.

What pressure are you running to the lockers?
 
What pressure are you running to the lockers?

The line that keeps blowing is the line going up to the gauges in the cab.

150 PSI is going to the main PSI gauge
120 PSI to the ARB gauge
110 PSI to the AIRock

You'd think the Main hose would be the one blowing if it was a PSI issue.
 
Been trading emails with tech support at SPAL most of the morning. They've sent me some troubleshooting info and I'm going to go try and see what I can figure out.

Brushless Fan/Sensor Installation Outline:


What are some things you can do to insure proper function from your SPAL brushless fan?

  • Connect the fan positive (red) and fan negative (black) wires directly to the battery.
  • The fan and sensor will communicate better if both devices are connected to the same voltage/ground sources.
  • The alternator can create electrical noise and variances in voltages that could cause intermittent communication with the PWM signal. Connecting the fan to the alternator can cause a non-functioning fan.
  • Systems with batteries mounted in the trunk.
  • Pay extra attention to how the fan is connected to +12V and ground. The added length of the wires can create voltage drop in the system if the fan wires need to be ran to the battery.
  • Battery power can be supplied to a junction under the hood, but it is best to have a dedicated circuit for the fan. If the fan is connected to a junction with many different electrical loads, voltage supplied to the fan could vary and cause intermittent function of the fan as the fan and sensor could struggle to communicate properly.
  • Corvettes (Fiberglass cars in general.)
  • Grounds can be different potentials at different locations around a vehicle. Sometimes these cars can have a difficult time having a consistent ‘ground’ connection in different locations around a vehicle. You may measure a few volts of potential difference between grounds. It’s best to have the fan/sensor be connected directly to battery power/ground.
  • Grounds can change as electrical devices turn on/off. Vehicle ‘grounds’ can be dynamic on modern vehicles as increasing electrical loads are added to vehicles. As electrical devices turn on/off on your vehicle your battery needs to supply enough voltage to maintain functions of the devices, but the vehicle must also have grounds sufficient to maintain +12V potential on the vehicle as electrical loads turn on/off on a vehicle. So providing a dedicated power/ground connection to the battery for the fan will result in the highest system reliability.
  • Fusing or wiring the brushless fans.
  • If you don’t know how much power your fan is capable of consuming contact SPAL USA. SPAL USA can also provide a fusing recommendation for your fan.
  • If you don’t know what diameter/type wire to use to install the fans, contact SPAL USA. We are happy to help make sure your install will support the loads of the fan. The following chart can be used in selecting wire diameters, we recommend maintaining less than 5% voltage drop in your wires.

Brushless Fan Trouble Shooting


This trouble shooting guide assumes you have installed the fan system according to SPAL USA’s wiring diagram, and you are trying to determine if the SPAL sensor/SPAL Aftermarket Fan System is functioning properly. These procedures will only work with SPAL Aftermarket ‘Plus’ version fans. If you have questions contact SPAL USA Technical Support.

  • Test the function of the sensor.
  • Apply +12V to the blue wire of the sensor. Does the fan start and run up to full speed?
  • Yes – Your fan system is working appropriately. Start engine and verify the fan comes on at appropriate temperatures.
  • No – Proceed to step ‘b.’
  • Measure DC voltage between the white/PWM wire (from sensor to fan,) and ground. (Both black wires, fan-ground or sensor-ground should work.) Measure voltages with the ignition key off and with the key on/engine off.
  • Key off should be battery positive voltage. ~+12.5V.
  • Key on should power up the sensor, and voltage will pull down to zero volts. (Engine must be cold, otherwise fan could run.)
  • If the voltage does not ‘pull down to zero volts’ when the sensor powers up, the sensor should be replaced. Verify function of the fan with a bench test. Replace sensor and repeat test procedure.
  • Bench Testing the brushless fan:
  • The fan has 4 wires that can be connected directly to a battery to have the fan operate at full speed. Follow these steps to bench testing the fan.
  • Secure the fan so it can operate at full speed safely.
  • When the fan is connected in the following sequence, the fan will pulse/wiggle, momentarily stop, then it will start up and ramp up to full speed. Connect the 4 wires from the fan to a battery as follows:
  • Red Wire -> Battery Positive (+)
  • Yellow Wire -> Battery Positive (+)
  • Black Wire -> Battery Negative (-)
  • White Wire -> Battery Negative (-)
  • Does the fan run at full speed?
  • Yes – The fan is behaving properly. Install the fan into the vehicle and proceed to test the function with the sensor. (Note: This test runs the fan off different internal motor circuitry than when it runs from the sensor. This is a ‘good’ test, but is possible to not be 100%. It’s possible the PWM circuit could be damaged, and the fan would function from this test but would be unlikely.)
  • No – Return the fan to SPAL USA for analysis and replace the fan.

So my connecting the Yellow wire to 12V didn't confirm anything. So I'm back to square one.
 
Been trading emails with tech support at SPAL most of the morning. They've sent me some troubleshooting info and I'm going to go try and see what I can figure out.





So my connecting the Yellow wire to 12V didn't confirm anything. So I'm back to square one.

Where is step 'b'?
 
Where is step 'b'?

It didn't copy correctly.
Step b is checking the white wire for 12V with the key off and the it should go to 0V with the key on engine not running.

I don't have 12V with the key off unless I unplug the temperature sensor.

I've got to send him the results of my tests and see what he says. But I'm still leaning towards the sensor being bad.
 
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It didn't copy correctly.
Step b is checking the white wire for 12V with the key off and the it should go to 0V with the key on engine not running.

I don't have 12V with the key off unless I unplug the temperature sensor.

I've got to send him the results of my tests and see what he says. But I'm still leaning towards the sensor being bad.

Is there a schematic?
 
Is there a schematic?

For the temp sensor or how to wire the fan & sensor?

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SPAL replied after I sent my results of my tests and he said that my results say the it may not be the temp sensor and that I should redo my wiring where I connect directly to the battery instead of going thru the Jeeps PDC. So on Wednesday I'm going to pull the wiring apart and connect it directly to the battery as they suggest and see if this fixes the problem.
 
Yes. Wasn't that the 1st step?

And NO my fan didn't come on like it was supposed to.

Did you leave that power on when you checked the white? That’s the only power with the key off so it’s the only way white would get 12V with the key off. If it doesn’t then the sensor must be bad.
 
Did you leave that power on when you checked the white? That’s the only power with the key off so it’s the only way white would get 12V with the key off. If it doesn’t then the sensor must be bad.

I followed the instructions that I posted. And from what the tech at SPAL said it might not be the sensor.
 
There’s no other power at that sensor without it when the key is off.

I don't know. I was just following the directions I'd gotten from SPAL.


I did some more testing and here is what I’ve come up with. But as you have said I do need to reconnect my wiring and have it running directly to the battery just to rule out any issues with connections.



Supplying 12V to the Blue wire does nothing.



With the key off I had 12V to the White wire only if I had the temperature sensor unplugged. As soon as I plug in the temperature sensor the voltage would drop to 0.06V. With the key on/engine off the voltage was 0.01 and then when the engine was brought up to temp the voltage was 0.04V.

I’ve got an appointment with the VA tomorrow so I won’t have a chance to work on my Jeep until Wednesday. I will rewire the fan and sensor wiring as you are suggesting and see what happens then.

I think that is good news because it looks like the sensor is powering up and pulling the PWM voltage down. At least that’s a sign of life from the sensor, so I believe we are on the right track.

The brushless fan uses a pulsed ground (negative type, sinking PWM signal.) The PWM controllers of old were designed to pulse the power wires to the fan. So you can’t really use the old PWM controllers with the brushless fans. But you could use a grounding temperature switch to turn on/off the new brushless fans, but this way you would only get on/off function. You wouldn’t get the variable speed without using a PWM sensor, or a brushless fan PWM controller.



To directly override the brushless fan two conditions need to be met:

  1. The white/PWM wire needs to be switched/connected to ground. When the White/PWM wire is grounded this is sending the fan 0% PWM speed request, but it causes the motor to wake up.
  2. Once the motor is awake, and asked to run at 0% PWM, the motor will look to the yellow wire for 2-10V analog voltage.


Red/Black should be run directly to the battery positive and negative terminals, you put a fuse on the red wire. No relays are required. The brushless fan was designed to basically ‘replace’ the relay. Then you just ground the white and power the yellow and the fan should ramp up to full speed.

The easiest test you can do would be the voltage pull down test. When the sensor is ‘off’ on a cold engine, you can use a DC voltmeter to measure the voltage on the white wire while it is connected to the fan. You should see the same voltage on the white wire between the fan and sensor that you see on the red wire going into the fan, ~12.5V. When the sensor powers on, this white/PWM wire voltage will pull down to 0V.



This test makes sure that the sensor is powering up and is a strong indicator that the sensor is functional. It’s not a 100% test as the override function is a separate part of the circuit board, but if the sensor pulls down the PWM voltage on startup it usually works with coolant temperature.



The most common issue we encounter with these systems are on vehicles where the battery is remote mounted. The fans need a dedicated connection directly to the positive/negative terminals of the battery for the best reliability. We find that on vehicles where the power/ground are shared with other electrical devices the communication between the sensor/fan becomes unreliable. The fan and sensor use a digital PWM communication so the voltages (power sources, and grounds,) should be connected/shared as much as possible. On vehicles where the fan positive wire is connected to a fuse block, alternator stud, or a starter, the voltage will fluctuate as other electrical devices turn on/off on the vehicle and this can lead to intermittent function of the fan. The same is true for the grounds, if there are several electrical devices grounded at the same location, they can interfere with the voltages the fan references as ground. Ideally the red/black wires for the fan would be connected directly to the terminals of the battery, with a fuse on the positive wire. The sensor power/ground is not nearly as touchy because the current draw is much lower, but the sensor does need to reference the same voltage/ground for them to communicate properly. For testing I would recommend connecting everything directly to the battery, then see if the override function works correctly.
 
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I would HOPE the tech at SPAL is the expert....

At this point I'm going to hook it up the way they are suggesting and see if I have any changes. If not then I will still go with the idea that the sensor is bad. I feel that it is but from the information I gave the tech he says it isn't.