Trouble with wire colors, diagnosing cooling fan on radiator.

[Larry Hampton]

Black car is a '92 GL auto with factory A/C. I have an '89 factory shop manual and I've printed the '92 wiring diagrams from this site.

My relay has two larger wires and two smaller wires, I figure the larger are the power side and the smaller the switch side.

I've always understood that the first color is the wire color and if there is a / the color after is the stripe.

The larger two on the pigtail are BL/R and BL/BK and if the go straight across, tie into W/BL and Y/BK on the harness. The smaller two on the pigtail are BL/W and Y and tie into BK and BK/W as above. The wires on the harness are all the same size.

The diagram shows the harness to have BK/Y, GN/Y, BK & Y/R. GN/Y goes to the temp sensor, but mine is Y.

The wires going to fan are Y & Y/R which matches the diagram, although the fan pigtail is BL/R & BL/BK.

I've jumped the fan, it works. I tried swapping the relay with a spare, the car wouldn't start (headscratch). Fuse is good too.

I tested both relays, the one on the car is good, the spare is bad (1. resistance)

When it overheated a couple weeks ago, and cracked the radiator, they were running the A/C on the way out to her folks, but not on the way back, when the belt broke.. The pump wasn't froze, just coolant out the pee hole.

[bravekozak]

You need the Staples scans.

I am not sure what relay you are describing. The wire colors are closer to those of the main relay, but not exactly. Please double check. First clean the wire with a little varsol (mineral spirits) to make sure of the color.

[bravekozak]

If the temperature switch is good (closed above 207F), follow the black wire from the cooling fan relay to make sure it has a good ground. When the A/C is turned on, the cooling fan should come on right away, since the black wire on the A/C relay also goes to ground when the relay is energized. The A/C relay is energized when the blower is not in the off position, the refrigerant pressure switch is closed (freon pressure present), the A/C thermostat detects a temp higher than it's set point and remains closed.
Ignore the colors of the pigtails. It is the colors of the harness wires looking into the backs of the connectors that are important.

[Larry Hampton]

Those are the ones that dont match. My A/C clutch is gone I think, I took the belt off the compressor. All sorts of red dust in that belt. Compressor may be bad too. If the clutch is easy to take off on the car (a million it isn't) Ill swap it with the one I was going to put on my car.

I can't read the PDF from my phone, Ill look at it on my computer in a bit. What confused me is there is supposed to be a wire from the relay to the fan, but its not the same color all the way. I only saw one relay, mounted to the overflow bracket.

[r34king]

The relay on the overflow bracket isn't for the fan. The rad fan relay is screwed to the inside of the driver fender. At least it was on my 93 5 speed and 89 auto

Sent from my SAMSUNG-SGH-I717 using Tapatalk 2

[bravekozak]

The cooling fan relay and headlamp relay are located beside each other below the back of the driver's headlamp. The cooling fan relay is on the left.

To check if the A/C compressor clutch works, put the belt back on, pull off the wires to the pressure switch and jump it. See if it will engage when you turn the A/C switch on for a second or two. Make sure you turn it off right away if you don't have any freon due to a leak somewhere. Blip the freon valve to see if there is any pressure left inside. Good luck.

[Larry Hampton]

I've got freon, it just doest cool. Clutch engages, maybe compressor is shot.

There is the A/C three round thingy relay under the battery, maybe I need to pull it to look for other relays.

[bravekozak]

The three round thingy from left to right is the A/C relay, Wide open throttle A/C cut-off relay, condenser fan relay. Only automatics have a condenser fan. If your cooling fan turns on as soon as you turn on the A/C, then your A/C relay is working. Wide open throttle relay disengages the compressor clutch when the ECA senses pedal to the metal. Those should all have nothing to do with proper cooling.

Have you inspected the evaporator inside your car? Remember, Festivas do not have cabin air filters. Twenty years of dust and dirt can certainly plug up the fins.
I have written before that Festivas also do not have a bypass valve on the hose to the heater core located in the blower housing. You may want to consider installing one for extra cooling efficiency. Why have hot coolant go into the blower housing when you are trying to blow cold air through it at the same time?

[Larry Hampton]

Good point on the lack of bypass valve, On my '65 Mustang, I had a hose connector on one of the hoses, during the summer I'd loop the heater core into a closed loop and hook the other hose back to the water pump.

And thanks for the scans, gosh I love having a plotter at work, plotted them 18x27

[Larry Hampton]

Okay, studying the scans, apparently the relay on the bracket for the overflow is the main relay, which is why the bad one wouldn't let the car start. The wire colors match up.

I was confused because even though there were only 4 wires going to it on the diagram, it appears it's a 6 pin plug, whereas the main is only a 4 pin plug.

I also think I was looking at the coolant temp sensor (Y/W, mine looked Y only although I thought I saw a white dash) as opposed to the cooling fan temp switch (should be GN/Y)

[bravekozak]

You still need to inspect the fins in your evaporator core. You may be in for a rude awakening. Has any small leaves an such ever gotten into your plenum? Do you drive with the ourside air damper open most of the time? If so, then uh oh! Be sure to read my thread entitled "cabin air filter". Be sure to post a picture after you remove your damper.

[Larry Hampton]

With the key on, on the yellow wire I get 12+ volts. It looks like I need to check resistance on the yellow/red between the relay amd the fan. If that checks out, then the yellow/red on the A/C power relay.

[Larry Hampton]

With the key on, on the yellow wire I get 12+ volts. It looks like I need to check resistance on the yellow/red between the relay amd the fan. If that checks out, then the yellow/red on the A/C power relay.

[bravekozak]

The cooling fan motor can ground through the cooling fan relay or the A/C relay.
Do you have power in the Blue wire from the A/C switch to the A/C relay when you turn on the A/C? The A/C relay grounds through the blower motor control switch.

[Larry Hampton]

I didn't get that deep last night, only spent about an hour on it as I got home late. When it gets dark, the bugs are thick so I usually shut down about 8:30. I tested the fan relay and it tested okay.