• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

91 Lx 5.0 r-12 to 134a issue

  • Thread starter Thread starter RedFox561
  • Start date Start date Oct 5, 2018
  • Tags Tags
    a/c compresser convertible hvac mustang lx r134a
R

RedFox561

New Member
Oct 5, 2018
2
0
1
West Palm Beach, FL
Oct 5, 2018
#1
  • Oct 5, 2018
  • #1
About 2 years ago I did the r134a conversion kit from late model resto. For almost 2 years it blew ice cold with no issues. I didn't run my car for about 2 months due rain every day so it just sat in my garage. I recently went out to start it up, turned the a/c on and its now blowing hot air. I don't have a set manifold gauges at home but I visually inspected the entire system, check all fitting and lines. Nothing seems to be out of order, no visual leaks. Anyone else done this conversion kit and had this happen? Or know any common areas that leak in these systems? The entire system in brand new, been ran maybe 10 -15 times since I don't drive my car that often. Any info would be much appreciated, its hot as hell down here in south florida. Thanks!
 

RaggedGT

Been here over a DECADE and still no CT
Mod Dude
Jul 20, 2014
4,739
3,188
203
Taylorsville ky
Oct 5, 2018
#2
  • Oct 5, 2018
  • #2
Is the compressor running?
 
Reactions: jrichker

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,813
234
Dublin GA
Oct 6, 2018
#3
  • Oct 6, 2018
  • #3
With the engine running, use a test light connected to the 2 wires on the A/C clutch harness to make sure you have voltage when you turn the A/C on. If the system is low on refrigerant, the clutch will not engage (safety feature, keeps you from burning up the compressor due to no oil). There is an aluminum canister on the firewall with a large hose leading to the A/C compressor. There is a pressure switch on it with a 2 wire connector: pull the connector off and jumper the wires. The compressor circuit will power up, and the test light will light if the electrical circuit is good. This test is also a good way to check the compressor & clutch if the system is low on refrigerant. You can jumper the wires and the compressor will turn if the clutch is good.

The clutch also has a relay that shuts off when you go to WOT (wide open throttle). It is located on the passenger side inner fender well. The close proximity of the relay to the headers can cause the insulation on the wiring and the relay socket to deteriorate. The relay can become non functional when this happens.


Diagram courtesy of Tmoss & Stang&2birds


See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
 
You must log in or register to reply here.

Similar threads

9
91 LX 5.0 getting hot when a/c is running
  • 91lx14gt5.0s
  • Jun 29, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
14
Views
218
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jul 4, 2026
manicmechanic007
D
Brakes 1966 Mustang convertible 289, Auto - Disc brake conversion issues
  • DRGunn427
  • Feb 26, 2025
  • Classic Mustang Specific Tech
Replies
5
Views
679
Classic Mustang Specific Tech Jul 23, 2026
All Stock93
M
Progress Thread mnky99 2001 V6 evap core, ac compressor, heater core replacement
  • mnky99
  • Sep 5, 2025
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
1
Views
515
1996 - 2004 SN95 Mustang -General/Talk- Sep 5, 2025
mnky99
M
Progress Thread 1993 LX Hatch Progress
  • Mac131
  • Aug 24, 2024
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 9 10 11
Replies
210
Views
12K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jun 15, 2026
Mac131
Place to Avoid: Jamison Auto Group in Gulfport, MS
  • D Durden
  • Oct 20, 2025
  • 1965 - 1973 Classic Mustangs -General/Talk-
  • 2 3
Replies
46
Views
3K
1965 - 1973 Classic Mustangs -General/Talk- Jul 16, 2026
Noobz347
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?