AC Relay Location

Tiny
BAGGAGE1
  • 1987 FORD TEMPO
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 147,136 MILES

Enter your question. Where is the AC relay switch on my 87 Ford Tempo. When I turn it on the radiator fan comes on but the compressor doesn't engage.

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Wednesday, November 24th, 2010 AT 1:16 PM

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Tiny
WRENCHTECH
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That relay is built into the engine cooling fan controller which is located behind the glove box.

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Wednesday, November 24th, 2010 AT 1:22 PM
Tiny
BAGGAGE1
  • MEMBER

If I understand this right then in order for the Compressor to activate then the A/C fan controller unit itself needs to be replaced. The relay EEC I take it is the Electronic Engine Control relay. The one next to that? I sure appreciate your knowledgeable response. I would imagine finding one of those would be tricky.

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Wednesday, November 24th, 2010 AT 8:42 PM
Tiny
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No, I'm not saying that this is the reason the A/C won't work. You asked me for the location and that's what I gave you. The circuit needs to be diagnosed properly to determine the reason for your problem.

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Wednesday, November 24th, 2010 AT 8:54 PM
Tiny
FIXITMR
  • MEMBER

Did the air work before or recently? Your compressor wont engage if it's low on freon. I beleive there is a pressure sensing switch on the canistor by the firewall pass side. You should be able to bypass by shorting the harness plug contacts together to see if juice is going to compressor. Dont try to run it shorted for very long. Just as a test.

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Thursday, November 25th, 2010 AT 4:54 AM
Tiny
FIXITMR
  • MEMBER

Of course, if you wish to add your own freon you will have to short it again yo get it to take freon.

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Thursday, November 25th, 2010 AT 9:51 AM
Tiny
FIXITMR
  • MEMBER

If you add your own freon, be sure to check what kid it takes first. You cant mix different kinds of freon.

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Thursday, November 25th, 2010 AT 9:52 AM
Tiny
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I don't recommend trying to add refrigerant to this system without having a set of professional gauges to monitor both high and low pressures and understand totally how the system works and exactly how much refrigerant it holds. This can be very dangerous and/or do a lot of damage to the system if done wrong. Those "death kits" sold over the counter should really be outlawed.

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Thursday, November 25th, 2010 AT 11:51 AM
Tiny
BAGGAGE1
  • MEMBER

The whole system has been professionally rebuilt with some difficulty in locating parts since it ate a bushing that blocked the system. It worked like a charm. I noticed the on switch would light up and the cool air would take some time to come on. Now the light comes on but the cool air doesn't come on at all. I hear or feel the radiator fan kick in which usually started the compressor also. It doesn't need freon. Is the A/C cooling fan controller the whole assembly shown? Or just the left end unit? It looks like Ford wouldn't have any of those lying around but maybe worth a shot.

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Thursday, November 25th, 2010 AT 1:11 PM
Tiny
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If the system was "professionally rebuilt", it would be their responsibility to make sure the system is operational. Simply throwing parts or refrigerant at it is not the soolution.

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Thursday, November 25th, 2010 AT 1:16 PM
Tiny
BAGGAGE1
  • MEMBER

You would be correct however if the part was not replaced when redone because it was not defective at the time they would balk. I will go back to them but I know what they will say. So do you.

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Thursday, November 25th, 2010 AT 3:21 PM
Tiny
BAGGAGE1
  • MEMBER

I took your advice and took it back to where they worked on it. They did some testing and came up with the pressure sensor was bad or it was low on freon. Last time it worked it was blowing cold so he put a bypass on the switch and it worked. In order to fix the pressure switch the system would have to be drained and the switch replaced then refilled with freon. I chose the bypass. By the way I checked with Ford for the A/C fan relay module. They didn't have one but it was 160.00. Appreciate your help.

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Sunday, December 5th, 2010 AT 3:55 AM
Tiny
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That is a serious mistake to drive that with that switch bypassed. That switch is there to save your compressor from starving from lubrication. It regulates the pressure and prevents it from going too low. Driving it with that switch bypassed will likely end with the system being destroyed

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Sunday, December 5th, 2010 AT 12:23 PM
Tiny
BAGGAGE1
  • MEMBER

Well I certainly don't want to destroy the system. But if I need to have the defroster work I will run it for a short time until the windows clear. Here in Florida I have run it for short times just mainly to get it cool then shut it off. I need to use my car until I get up to SC. Then I can use my sister's car, and then I will put mine in a shop to get the switch repaired.

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Tuesday, December 7th, 2010 AT 1:46 AM
Tiny
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Believe me, I have heard every reason in the world that people have used right before they do serious damage to their car. It's never worth it, regardless of how important whatever you had to do is.

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Tuesday, December 7th, 2010 AT 1:49 AM
Tiny
BAGGAGE1
  • MEMBER

You have to understand I feel where you are coming from. I have wrenched all of my vehicles sans this one cause I'm retired. I do the oil and keep tabs on all the systems. I have replaced all non engine modalities, including another transmission. I have yet to kill a vehicle as in motor. This one has my full intention of driving it until the wheels fall off. I will tow that motorcycle which has the same displacement motor the car has. One gets out of it's own way the other has 148000 and runs like a top. My sister owned the car before me. She kept it up but didn't drive it everyday like I do. Everything works on it and I keep it that way. I'm not the average dolt with machinery. I understand every aspect of what happens when I turn the ignition on until I turn it off. And I know running that compressor constantly would probably do it in. The pressure sensor tells the AC compressor when to come on and when to disengage. The disengage I do manually when it has done what I want it to do.

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Tuesday, December 7th, 2010 AT 2:21 AM
Tiny
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No problem, do it your way

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Tuesday, December 7th, 2010 AT 2:23 AM

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