Heater issues?
I just went through two weeks of trouble shooting my heater. It refused to work and I blew at least 6 fuses before I got it right. Lucky for me I got some help from some folks on line. This helped out a great deal.
Before I get to the steps there are 4 parts of the heater system:
1. the heater motor
2. the heater resistor
3. the fuse
4. the switch
What I did not realize before I got into all of this is that the switch is also where the system grounds it self. That is not how I thought it would be. So let me paint you a picture. (I am not an electrician so I may get my terms etc wrong, this is how I figured out my problem)
-Basically the power goes from the fuse box to the motor BROWN WIRE
-then from the motor the power continues to the blower motor resistor YELLOW WIRE
-from the resistor the power will run down one of 3 wires (depending on where the switch is) to the ground.
When the switch is in the off, there is not power going to the ground.
In any of the speeds the power is then grounded causing the motor to turn. Speed is dependent on which resistor is grounded.
I have attached the wiring schematic below. If your confused now, this should help.
Now here are the TROUBLE SHOOTING STEPS the were a big help to my trouble shooting, maybe they will help you.
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1) with the key in the "off" position, you should have NO POWER at the brown wire male connector at the blower motor. IF YOU DO HAVE POWER with the key in the "off" position, then you have a short somewhere between the fusebox and the blower motor. Not a good thing.
2) With the key in the "off" position, you should also have NO POWER at the yellow wire female connector that is under the dash that connects to the heater resistor package. In other words, pull the yellow wire off of the heater resistor package, and with the key in the "off" position, you should have NO POWER to that yellow wire at all. This is what MR. TIM was talking about. IF YOU DO HAVE POWER THEN THERE IS A SHORT IN THAT WIRING! SOMETHING WOULD BE FEEDING BATTERY POWER TO THE HEATER RESISTOR PACKAGE DIRECTLY
3) Next, take the three pronged female connector off of the heater resistor package. This will take the dash switch out of the picture.
4) Next, remove the female yellow wire connector from the heater resistor package. This will take the heater resistor package out of the picture.
5) Now put the key in the start/run position, you should now have power at the brown wire male connector at the blower motor under the hood. ( this means that the battery power is getting to the ignition switch, and the ignition switch is only providing power to the blower motor when the key is in the proper position, which is a good thing).
6) with the key still in the start/run position, you should also have power at the yellow wire female connector under the dash that you pulled off the heater resistor package. IF YOU DONT have power at the yellow wire, then you have a short between the blower motor and the heater resistor package. Just replace that yellow wire.
7) IF the yellow wire has power, put it back onto the heater resistor package. BUT KEEP THE THREE PRONGED CONNECTOR OFF THE RESISTOR PACKAGE. with the key still in the start/run position, now get your test light and connect the aligator clip to ground. With the test light, touch one of the prongs on the heater resistor package. Each prong should light up your test light AND make the blower turn on! Each prong on the heater resistor package will turn the blower at a different speed. DO NOT ACCIDENTALLY TOUCH TWO PRONGS AT THE SAME TIME!!!!! Only touch one prong at a time. IF EACH PRONG turns on the light and the blower motor, then the heater resistor package is GOOD. IF it doesn't, then you have a bad heater resistor package.
8) If you made it this far, then the only thing left is the heater switch/wiring harness with the three pronged female connector. The 65 heater switch and the 66 heater switch are not interchangeable. The "off" position on the 65 Switch is in the center. The "off" position on the 66 switch is to the far left. You MAY have the wrong year switch on there. IF your absolutely certain that you do have the 66 year switch on the car, then you have a short in the wiring in the switch. EITHER WAY, you would need a new heater switch/wiring harness.
9)
A) DISCONNECT the harness leading FROM the resistor pack TO the fan speed switch before proceeding.
B) Connect the plug from the harness that connects switch to the resistor pack ONTO the resistor pack (on the red panel on the front of the heater box under the dash). MAKE SURE that the connector is NOT connected to the fan speed control switch.
C) With the ignition key in the start/run position, insert a probe with a jumper wire connected to ground into EACH of the 3 terminals in the fan speed control switch connector. The fan motor should run at 3 different speeds.
10)
A) Connect one side of your volt meter or test light to ground and with the ignition key in the start/run position, and the harness connector to the resistor pack OFF of the switch, turn the switch to the OFF position and touch your test light to EACH of the 3 tabs on the switch.
You should NOT read voltage or the light should NOT light.
B) Switch the switch to each of the 3 positions (low-med-high) and probe for voltage or light on each of the tabs.
These tests will test the way the circuit "SHOULD" work. The fact that you were blowing a fuse when you turned the switch ON tells me that somewhere there is a short between power and ground.
Please per form these tests and let me know what happens.
I have a attached a large picture of the wiring schematic. I left it large so that you can read it to follow it.
The wire numbers and colors are: Wire #181 = BROWN and Wire #913 = YELLOW. The wires between the resistor pack and the switch may be any color.
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66acessories.doc | |
File Size: | 309 kb |
File Type: | doc |