Hi Ford Ranger Family,

I need some serious advise. I live in Miami, Florida. SUPER HOT & HUMMID! My A/C gave out yesterday!!!
I am a weekend mechanic and have some mechanical and electronically knowledge of repairing vehicles that I have picked up throughout the years. But this has me super puzzled. In the morning my A/C was working just fine. I disconnected my battery, changed my oil, swapped out the temperature gauge sensor on the manifold with a new one & reconnected my battery back up. Jumped in the truck, started it up to check if the temperature gauge would work now that a new sensor was installed (reason for new sensor, truck always read cold, never made it past first line). And being temperatures outside are in the high 90's this time of year, cranked on my A/C on high and only got hot air.

Okay, so if I leave A/C turned on high, turn off the vehicle and turn it back on, the compressor turns on for like 2 to 4 seconds and disengages. If I jump the compressor with power straight to the battery it engages and I have cold air. I thought it could be the low pressure sensor because I jumped the plug once and the compressor came on. So I changed it out. Nothing! So I tried to jump it again on the low pressure switch and now it has no power. I have checked all the fuses under hood and in cabin, all good. I even disconnected my battery again for 20 minutes and reconnected it thinking it might be the computer needed resetting, nothing. I bought a can of 134 and connected the hose with gauge that came with it to the low end and it read over 100. I don't know if the gauge was wrong or what. Any ideas would seriously help.

Does anyone know if it can be one of the resistors in the fuse box under the hood? And if so, how would I check them? There is two sizes. The bigger one reads, FOAB 14B192-AA 8240-2 20 2R and the smaller one reads F576-14B192-AA.

Oh yeah, one more thing, now my check engine light is one and it wont shut off.

Thanks for reading and any suggestions or info you can advise, thank you.

Carlos

 

The A/C compressor has a wire harness (one wire) that connects to the A/C clutch. Trace this wire throughout the engine compartment to see if it got cut, broke, or disconnected from another connector when you were changing the temp sensor. You may have aggrivated a bad connection without knowing when you were doing this work. The fact that you were able to jump a lead from the A/C compressor straight to the battery and get it to work tells me it (A/C compressor) is good. Does the system blow cold air when you do this? The A/C compressor operates when there is pressure in the system; if the freon leaked out (could you have leaned on one of the pressure lines when you were working on the temp sensor, or around the condensor by the radiator?), the A/C compressor will do as you described; it will cycle on for a second or two, then turn off if it detects it is not "compressing" or building pressure, which is required for the gas to effectively cool. An A/C system does not actually cool air, but rather the freon "removes" heat, and for this to work, the freon is compressed by the A/C compressor, making it very hot. Then, the hot Freon gas moves through the condensor (in front of the radiator), which has the effect of lowering its heat and converting it to liquid. The Freon liquid then flows through an expansion valve, which causes it to cool down until it evaporates. The result is low-pressure Freon gas. The cold gas is then channeled through the evaporator (in the large box by the passenger side firewall). This allows the gas to absorb heat and lower the air temperature. The fan blows this cold air through the vents in the cabin.

 

First and foremost pull the codes...

Double check, with a TEST LIGHT, the following fuses: Fuse #10 (7.5 amp) in the IP fuse box. Mini Fuse #1 (10 amp) and #8 (30 amp) in Power Distribution Box (PDB) under hood.

For the layout of the PDB click this link Owners Manual and go to roadside emergencies.

If the fuses are good and with the engine running, set the selector to AC, pull the AC low pressure (cycling) switch and jump the black with yellow stripe wire to chassis ground. If the AC now works, connect your test light to the battery positive terminal and probe the red with yellow wire. Test light should light up. If not, check the AC high pressure switch and associated ground.

If the AC did not come on after jumping the low pressure switch and the high pressure switch and ground circuit are good, pull the AC control relay and verify your getting power from the PCM Power Relay to socket terminal 2. If you have power, connect your test light to the battery positive terminal and probe socket terminal 1 (test light should light up).

If test light lights up, you'll need to pull the dash center panel so you can get to the AC control panel wiring. Once you have the control panel out, look for a purple wire from the selector control switch. Probe this wire and verify you have power at this wire.

If all the above checks good you'll need to check the wiring at the PCM side.

Note, pressure reading without the AC compressor running wont tell you much. However, 100 psi is in the ball park.

If you want a copy of the wiring schematics, PM me a email address and I'll send you a copy.

 

Not cool.

Pun intended.