Ford Repair Questions? Ask a Mechanic for Answers ASAP
take a look at the wireing pic below
as you can see there is a fuse in the interior fuse panel that runs through the a/c switch on the dash , and then goes to the low side switch ,, so start at the low side switch and see if there is power there with the key on and a/c om,,,if not then check that fuse in the car ----if there is power at the low side cycling switch ,,then jump the two wires together and move to the high side switch for the a/c ,,this switch should have power going into it and out of it ,,,if it does not then the high side switch is bad.. tell me what you find ,we can go back and forth on this page
I've jumped & tested these but i'll try again. I found B+ at the switches & tested the switches w/ a VOM & got full continuity through them (no resistance). I'll try again...
ok power runs through the low side switch and then through the high side switch ,,and then to the relay ,,,
also if you remove the relay for the a/c and look on the bottom of it ,,there is numbers next to each pin on the relay ,,, pin 30 and pin 86 ,ware they go into the fuse box should have power on both of them , with engine on and a/c on,,,see if both do or not , with the relay removed see if these two pins ware the relay goes have power
B+ across both switches; no resistance on switch pins; jumpered both switches, no change. Compressor will still only operate if I jump the relay pins from comp feed to PCM B+ feed (relay out). Otherwise, no comp...
W/ key "on", I have B+ from #86, .25 (1/4)V on #30 & a couple of millivolts on #85...
BTW, relay clicks when plugged in w/ key on...
ok, did you remove the relay ,, turn the a/c on and car on ,,and see if you have power at pin 30 and 86 in the fuse box ware the relay went ,,,, with all switches back in place
below is a pic o the low side switch mounted to the accumilator ,number 4
and below is a pic on the high side switch ,called the cut off switch
OK, more testing. B+ (12V) at high-side connector (red one); checked continuity from that connector to pin 30 (no resistance, ckt closed), so wire is OK. High-side switch has no resistance (closed) on pins. Is switch still bad..? Does the system have to be evacuated & re-charged to replace it..?
I still get no voltage if I jumper the connector..? WTF..?
Here are my findings, which have me more confused than ever. I have 12V to Gd on one pin of the h-side connector (w/ IGN & A/C on). I have ZERO resistance on the other pin to pin 30 @ the cutoff relay. But when I jumper the connector, all I get at pin 30 is .25 volts. What am I missing here..? There HAS to be a feasible explanation.
No offense taken. Yes, I know how to test. When I place one probe (w/ VOM set on 20K ohms) on the pin one the high-side connector, and the other probe to pin 30, I get no resistance (zeros on the readout, it is digital), same as when I touch the 2 probes to each other w/ the same ohm setting...
hay ,,,thats a good test you are doing to find ware the problem , is ,, now move to the low side switch and try the hot wire there and run it to pin 87 ,,, if thats ok ,,, plug the low side switch in ,,, then tap into the other wire of the low side switch , key on , a/c on ,, and run it to pin 86 ,,see if it turn the compressor on ,,,, this will help narrow down ware the problem is
Same result. I have the same voltage reading (13+V) coming from both the PCM feed and the lo-side feed. Yet when I jum the lo-side feed to pin 87 I get nothing; when I jumper to the PCM feed the compressor engages (even w/ identical voltage readings on both jumpers)... Is this an amperage issue perhaps..? Why will it run from one 13V feed and not another..?
Jumper from fuse 5 B+ to pin 87 operates the compressor (same as PCM B+). Next test..? BTW, changed out fuse 5 (it looked OK) & no change... So it wasn't the fuse.
Sorry about your collarbone <ouch>, I'm working in 90+ SoCal heat but I'm used to it. I hate cold... LOL
the panel around the a/c switches pops off,,, then there is four 7 mm bolts that hold the control head in place
Grabbing my metric crescent wrench... ;o)
I have tried the following "jumps" with these results: From p/o (where I have power), to the compressor side of the lo-press sw, no comp; from p/o (control head) to comp side of hi-press sw, no comp; from p/o (CH) to pin 30, comp activates.
These tests were unplugged, let me plug 'er in & try again...
lets go back a little again ,, unplug the control head ,, jump the p/o to the p on the control head conector ,,,,, then go to the low side switch p wire and jump that to 87a in the relay fuse box for the a/c relay ,,,, does the compressor engauge ??????
OK, after a multitude of tests, re-tests & all else, I finally got the compressor to engage by jumping the p/o & p wires w/ the control head plug disconnected & all else re-connected. That isolated it to the control head switch. Cleaning did not resolve the issue, so now I know that a replacement control head is what I need. I thank you so much for your time, & patience, & hope your collarbone heals quickly. Please respond so I know you got this message & I will accept & checkout. Thanks again..!
ok,, thats ,, good, thanks,
ok, never has this problem on any other unit like this ,,