1991 GT Vert…Reinstalling removed factory A/C

[BillyMoore]

I’m new to the forum and a new old mustang owner…I recently purchased a 91 GT convertible. The car was on its way to becoming a drag racer but is still relatively stock. I plan to take it back to completely stock…The previous owner removed the factory A/C, and it looks like the power steering pump may have been repositioned. I’m trying to figure out how to mount the compressor, locate the compressor and pressure switch wiring. Also the condenser has been removed and there is an electric fan installed…is the electric fan an aftermarket add on? I can’t remember seeing an electric fan on a car this age.

Any tips or help will be greatly appreciated.

 

[General karthief]

Give us a shot of the engine to determine the PS position and no, a 91 mustang did not have an electric cooling fan.

 

[Mustang5L5]

Need a pic to see if oyu have the Power steering relocation kit, but generally you need these brackets to reinstall the a/c compressor.

https://lmr.com/item/LRS-9998929-K/mustang-ac-compressor-bracket-hardware-kit-85-93

There is an A/C subharness that plugs into a plug down near the coil under the starter relay.

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And then there is a plug that plugs into the low pressure switch on the accumulator bottle on pass side firewall area. Plug should be dangling. that's really it for electrical.

No e fan in 1991. If oyu are missing the condensor mounting brackets, those are here.

https://lmr.com/item/LRS-19712BRKT-K/mustang-ac-condenser-mounting-bracket-kit-82-93

I would highly recommend all new lines, or flush the parts that you end up reusing. Any dirt/corrosion/etc inside can clog the system up quickly. Cleanliness is critical.

 

[BillyMoore]

The dryer, hoses and condenser have been removed so I’m going to buy the full kit from LMR. Also…car has headers and a cam which I’m leaving so won’t be completely stock.

If you look close at the front of the distributor there is a wire with plug on the end at about where the AC compressor should be. Im guessing this is the comp signal wire . I haven’t had a chance to check it for voltage.

It looks like I’ll have to replace the heater core so I’ll have to dig around where the dryer should be so hopefully I’ll find the wire for the pressure switch.

 

[Mustang5L5]

The plug near the dist is the SPOUT plug used for setting timing. That’s not it. Look near the starter relay underneath. The ac harness is actually a 2 foot sub harness that plugs into the main harness there. Round connector. 2 pins. Black.


The other pic by the fireall is slightly offset to the right. Look about 6-8” to the left side and the plug should be around there.

Little dark but this is about where it is. Comes out of the main harness in this spot

 

[Mustang5L5]

Also, your accessory brackets on there now are the ford OE brackets for no a/c cars. You will need to purchase the above kit (or find OE brackets) as the ac compressor brackets will mount like this.

(Ignore the power steering reservoir)

 

[BillyMoore]

Thanks for the help, I found both the compressor harness and the dryer harness. I’m about to change the heater core and clean the engine bay up…gonna start gathering parts hope to start on AC install in a couple weeks

 

[BillyMoore]

So yesterday I ordered the A/C conversion kit from LMR, along with compressor bracket, accumulator bracket, and compressor sub harness. The kit comes with compressor, condenser, hoses, etc so I should have everything I need to get the A/C back into the car. Would anyone be able to send a couple of pictures of an engine bay with attention to the routing and securement of the high and low pressure hoses? It should be somewhat self explanatory but a guide is always nice. Any help is appreciated.

 

[Mustang5L5]

Unfortunately no hood way to show the line routing. Too much stuff in the way.

Some in progress pics you can kinda make out the routing.

 

[BillyMoore]

This is helpful, thanks!