My dad has a 2002 Ranger xlt 4.0 with 45,000 miles. I tried to replay A.C. relay because Ac doesn't work now the truck won't start at all. I'm responsible for cleaning up his truck so he can sell it so I was trying to get his A.C. to work. Any ideas?

 

Welcome to the forum

"Doesn't start" can mean a few things
When you turn the key nothing happens, no lights come on, no Rapid Flash Theft light, and starter motor doesn't turn engine
When you turn on the key lights come on, no flashing but starter motor doesn't turn engine over
When you turn on the key lights come on, starter motor turns engine over but engine doesn't start.


I know what you said is clear to you, because you are there, but "no start" covers alot of ground

You most likely blew a fuse in the engine fuse box, did you remove any other relays?


There are no direct connections between AC system and engine running or starter motor
The PCM(engine computer) does control it all, including AC, but no common circuits inside PCM, or shared fuse outside

Actually not quite true, AC Relay and PCM power relay do share fuse 29(cab fuse box), and the PCM Power Diode(engine fuse box)


As far as why AC doesn't work, most common issue is the fluid level is low, so Pressure switch won't let AC Clutch relay close
AC systems have 2 pressure switches, low pressure and high pressure
If Freon gets low then low pressure switch will open so no power to AC relay
If AC system has a blockage then high pressure switch opens and no power to AC relay

You can test both switches with an OHM meter, remove connector, then touch the two pins with the 2 probes, 0 Ohms means switch is Closed so not the problem