no heat
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Joined: Aug 2002
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From: frisco
no heat
right now my 87 n/a has no heat and im not sure what the problem is.could the problem be the heater core or the hot and cold adjusting switch or what.it hella sucks because i cant defrost my front window and using that defog stuff aint really cutting it.
wet drifting dream
Joined: Sep 2003
Posts: 161
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From: Earth
it's more than likely the motor that actuates the valve on the heater core!! I have a 86 fc that had the same problem..I just disconnected the lever from the actuator so I can manualy operate the valve..The valve is located on the right side of the car.You will have to dig down thru some plastick to get at it...I at first thought it was the core it's self..I tore my dash board apart to get at the core that was when I found the valve on the drivers side..You wont have to tear apart your dash to do this mod..I will take some pics if you need them...
Former Moderator. RIP Icemark.
Joined: Apr 2001
Posts: 25,896
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From: Rohnert Park CA
Did you search??? The search function is found in the upper right hand corner of this page. I guess I will cover it again
Anyway just test the air mix motor, that will tell you if there is an electronic or actuator problem with the heat.
To test the air/mix motor (which the Logicon controls for heat or cold).
If the air/mix motor is good, then chances are the Logicon is bad. I have rebuilt ones available on my website, PM me if you need the address.
Anyway just test the air mix motor, that will tell you if there is an electronic or actuator problem with the heat.
To test the air/mix motor (which the Logicon controls for heat or cold).
So, there are three plugs at the Logicon. Two that plug directly into the back, and the third plug that runs off into the dash and plugs in above the air mix motor in the dash.
We are going to test a couple wires at that third harness.
So unplug that third harness. You now have a car side and a Logicon side. We are going to be testing on the car side of the plug, not the Logicon side.
We need to find the Green w/White stripe wire and the solid Yellow wire in that plug.
Putting your multi-meter on the wires, check for resistance (ohm). Resistance should be between 17 and 21 ohms at 70 degrees F.
If that checks out fine, then jumper 12 volts onto the Yellow wire, and ground onto the Green/white. The motor should move all the way over to the hot position.
If you reverse the two, (12volts on the Grn/wht and ground on the yellow) the motor should move all the way over to the cold position.
You only want to put the 12Volts on the wire until the motor gets to the hot or cold side. Remove the 12 volts after its there.
We are going to test a couple wires at that third harness.
So unplug that third harness. You now have a car side and a Logicon side. We are going to be testing on the car side of the plug, not the Logicon side.
We need to find the Green w/White stripe wire and the solid Yellow wire in that plug.
Putting your multi-meter on the wires, check for resistance (ohm). Resistance should be between 17 and 21 ohms at 70 degrees F.
If that checks out fine, then jumper 12 volts onto the Yellow wire, and ground onto the Green/white. The motor should move all the way over to the hot position.
If you reverse the two, (12volts on the Grn/wht and ground on the yellow) the motor should move all the way over to the cold position.
You only want to put the 12Volts on the wire until the motor gets to the hot or cold side. Remove the 12 volts after its there.
Last edited by Icemark; Oct 22, 2003 at 10:29 AM.
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