Yet another fan question....

[Skye]

Ok, I've searched and saw the other posts regarding wiring the fan, but there's something I'm missing.

The fan, at the plug goes:

WIRE SIDE__to_____FAN SIDE
blue_______to______blue
black______to______black
yellow_____to______blue

So, the black is ground. If I direct wire the ground to a ground, then hit the yellow side blue with a hot wire, it kicks on. If I hit the blue side blue, it won't come on. Am I wiring this correctly? Am I safe in assuming that one speed is gone?

I was having a problem with the AC kicking on and off so I'm assuming the fan id dying. Also, if the car is hot OR COLD, and I turn the AC on, the fan will not come on. I've proven that the high speed relay works, the fan fuse is good, can't test the low speed relay. It's stumbling, running like crap, especially when warm.

Am I on the right track here?

[CREWZIN]

The fan should come on when the A/C is turned on, no matter how hot or cold the car is. If it doesn't, you have one of the speeds of the fan motor burnt out.

When you hooked the wires up how loud was the fan. The high speed is really loud whereas the low speed is a normal fan motor sound. I know that sounds crazy but if you heard both going you can surely tell the difference.

The problem is, your not overheating (you didn't say so) and the A/C is kicking on and off. That's a sign of low R-134 in the system.

You might have more than one problem.

[Skye]

Well, my head was right at the fan, so it sounded loud, but it may not have been. I'm not sure which one the yellow is, but that one seems to be working. Regardless, it's not turning when the car is warm, with the AC on or off.

I don't think she's had an overheating problem, it's my wife's car, but I don't think so.

I noticed that it ran pretty well when it was cold. When I turned it off then started it again once warm, it ran like butt. I can only assume the computer doesn't like that the fan isnt turning when the car is warm?

[CREWZIN]

Well, no, the PT should actually run better when it's warm, it just doesn't like it HOT. The 02 sensors don't start working until the engine warms up so that could be a problem. What mileage do you have and when was the last time plugs and wires were changed? One thing at a time, if the fan's not running with the A/C on, one speed is burnt out. I've heard you can buy just the motor and not the whole housing but it all has to come out of the car anyway. If your handy, the right tools, about 2 hours work.

[Skye]

Mileage: About 75K
Plugs: I replaced them and the wires about 3 months ago.

Well, while it ran well with the car cold, I still think it's missing a bit. I replaced the O2 sensor before the cat just in case that was the prob, seems to be the same as before... just my wallet is lighter!

Fan, well as you say, one problem first. Apparently the fan has a prob since it's not coming on with the AC, so I'll address that next. One question, the fan not coming on, will that send bad info to the computer and cause it to run rough?

(thanks for the info by the way!)

[CREWZIN]

Originally Posted by Skye

One question, the fan not coming on, will that send bad info to the computer and cause it to run rough?
(thanks for the info by the way!)

No, but if the engine gets hot, that will surely cause it to run rough. Take a look at these querries about hot engines......

engine rough when hot - Google Search

[Skye]

So, technically if the car was without problems, I could disconnect the fan, let it run so long as it stays normal operating temperature and it should run like a top with the AC is off? (in theory)

I'm just trying to make sure I understand the fan's place in how the car runs.

[CREWZIN]

But it wouldn't run normal for very long a time without moving. It would eventually get hot, overheat, boil over and may warp the head.

But yes, your right. There is NO fan above 35mph. All speeds of the fan are cut off as the air moving threw the radiator is enough to keep it cool, even with the A/C, so you could run it without the fan forever, with A/C, as long as you kept over 35mph.

I overheated in Orlando (100 miles from home), it threw the red sticky anti-freeze from the overflow bottle all over my exceptionally clean engine. That was the worst part, the cleanup after. I let it cool off a bit, filled the radiator with plain water (that's all I had) and drove the 100 miles back home with the A/C on without a problem. Temperature guage stayed in the middle. 90% of it was highway driving and when I came to the city and saw a red light ahead I'd slow down as best I could and tried to wait till it turned green so I wouldn't have to come to a stop.

[Skye]

Gotcha, that answers my question.

I just wanted to be able to disconnect the fan while it's idling (engine still cold) to eliminate it from the loop of possible problems. Not 100% sure this will accomplish this, but it's something.

[TurboMoparDave]

Our PT was having similar problems with the A/C cycling on and off and running rough last summer. Took me a while to troubleshoot it, but turned out to be the low-speed of the fan. What was happening is that once the A/C had been on for a bit with no airflow the condensor got hot and the pressure in the A/C system got very high. The A/C system has a pressure switch, which turns off the clutch if pressure is too high. The pressure would spike, the clutch would turn off, then the pressure would drop and it would re-engage, similar to how a system low on refrigerant acts. Every time the clutch engaged the engine shuddered and wanted to die because the load from the A/C was much more than normal.

Pretty much what I'm saying is that it sounds like your on the right track thinking it's a fan related issue.