# 1993 B13, AC shuts off if blower on 4



## KSSteve (May 25, 2006)

I just bought a 1993 B13 with 136,000 miles. The AC works fine when the blower is set on 1, 2, or 3, but the compressor kicks off when the blower is set on 4. Any suggestions?


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## jakehale (Aug 8, 2004)

KSSteve said:


> I just bought a 1993 B13 with 136,000 miles. The AC works fine when the blower is set on 1, 2, or 3, but the compressor kicks off when the blower is set on 4. Any suggestions?



does the compressor kick off or is it the fan that cuts off? I mean just because it stops blowing, doesnt mean the compressor cut off....

if it is the fan and it works on all but 4,,, it is the switch in the console, the one your sliding over to 4,,,, simple to change.... if it was the other way around (nothing but 4) i would lean towards the blower reistor, another easy change.....

for now go with the switch, I had the EXACT same problem, swapped the switch and all is well......

Have fun


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## KSSteve (May 25, 2006)

The blower keeps going, but the air gets warm.


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## HATEnFATE (Dec 24, 2002)

interesting....

I would check to see how much refrigerant is in your system. If your compressor senses a high or low pressure situation it will shut down. If your system is low on refrigerant it could cause a low pressure situation and maybe shut it down.


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## KSSteve (May 25, 2006)

I'll check, but I don't think that's it. The AC works great with the fan set on 3 and it's been very hot here this last week (Kansas.) Also, the compressor seems to kick off instantly when I turn the switch to 4. I think it's electrical.


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## jakehale (Aug 8, 2004)

well it must be..... For the life of me I cant think of why your compressor would kick off..

For me though if you have access to a local yard I would just try the switch. from the yard those things run about $5, if you buy it new it is like $40.

Based on what you said I dont see it being the switch,,,, but for $5 I would give that a try


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## HATEnFATE (Dec 24, 2002)

Don't buy a used switch. NEVER buy a used fan switch for a B13.


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## jakehale (Aug 8, 2004)

Used switch worked fine for me, and its been over a year...... I know the theroy behind a new switch, but Mine is still kicking...


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## KSSteve (May 25, 2006)

It is a bad switch. The compressor goes off and the green light goes out if I move it to 4. If I move it 1/2 way between 3 and 4 I can get the compressor and green light to stay on, but it blows on high.


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## 92se5speed (Aug 22, 2006)

I have a compressor on/off issue myself. R12 in the 92 blows super-cold, but randomly turns off after maybe 5-10 minutes of driving. I checked my pressure on the low side one morning when everything was pretty cold, and it read about 52 psi. I assume that's too high? 

My passenger side cooling fan is also dead, so perhaps I'm not cooling my condensor enough. Problem is the same going down the highway at 80 though, so perhaps something else is to blame? No idea what the pressure is when it cuts off.


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## Rolling_over12 (Jun 29, 2006)

ok question does the the 4th blower slow down any afteron for a while mine would do thatbut My alternator was putting out enough to run it all check that or ull be dead on the road too


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## KSSteve (May 25, 2006)

92se5speed said:


> I have a compressor on/off issue myself. R12 in the 92 blows super-cold, but randomly turns off after maybe 5-10 minutes of driving. I checked my pressure on the low side one morning when everything was pretty cold, and it read about 52 psi. I assume that's too high?
> 
> My passenger side cooling fan is also dead, so perhaps I'm not cooling my condensor enough. Problem is the same going down the highway at 80 though, so perhaps something else is to blame? No idea what the pressure is when it cuts off.


The compressor on mine also shuts on and off more than any car I've ever owned after 5-10 minutes, and at first I thought there was something wrong. But since I got the blower to work on 4, it keeps the car quite cool even when it is 105 outside, so I'm not complaining. I'm assuming that it works that way to keep the evaporator from icing and to save fuel, but that's just a guess from someone who is a long ways from being a mechanic or engineer.

I did check the pressures one hot day, however, and the low side was lower than 52. Are you sure the compressor was running when you read the gauges? Does it keep your car cold?


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## KSSteve (May 25, 2006)

Rolling_over12 said:


> ok question does the the 4th blower slow down any afteron for a while mine would do thatbut My alternator was putting out enough to run it all check that or ull be dead on the road too


Battery is fine. Alternator is fine. It really is the switch. Works just fine if I can find the sweet spot between 3 & 4. Blower does not slow down on 4 if I find the right spot.

I just bought a new switch from NAPA for about $28, but haven't gotten up the energy to replace it yet. Maybe this weekend if it is cooler outside.


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## 92se5speed (Aug 22, 2006)

KSSteve said:


> The compressor on mine also shuts on and off more than any car I've ever owned after 5-10 minutes, and at first I thought there was something wrong. But since I got the blower to work on 4, it keeps the car quite cool even when it is 105 outside, so I'm not complaining. I'm assuming that it works that way to keep the evaporator from icing and to save fuel, but that's just a guess from someone who is a long ways from being a mechanic or engineer.
> 
> I did check the pressures one hot day, however, and the low side was lower than 52. Are you sure the compressor was running when you read the gauges? Does it keep your car cold?


We've had some hot weather here in Chicago too, and I certainly haven't melted when the compressor turns off, but it's off long enough for the air to start feeling humid and warm, then it kicks back on and gets freezing cold again. Rather annoying to keep feeling the differences in temperature. I can understand the idea behind turning off for a bit to keep from freezing the evaporator or to save gas, mine just seems to stay off much longer than needed. 

I think first thing I need to get both of my radiator fans working properly (passenger side fan just doesn't work, despite getting power to it) then evaluate the situation. I actually found a can of R-12 in my garage, so if I need to give it a bit of juice, at least I have some and a professional set of R-12 hoses (dad doesn't get much use out of em at the Nissan dealer anymore).


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