A/C cooling fan inop on high speed, when A/C requested

[gnray76]

Hi, having a problem w A/C Im hooking back up after ten yrs. everything works and turns on, but when A/C request, fan don't come on until up to temp..should come on with request.
now the fan is aftermarket single, did find both the black w pink tracer wire an black with red tracer wire to be tied together, have to say from resistor being removed, not by me....
so fan kicks on high when vehicle up to temp.
new delay relay, both high an low relays working properly,
also when diag. the relay, it should be requesting fan to come on, but dont...
I have a BS3 computer, so not orig. computer which I read fan turns on w ECM?
an is there anyway of bypassing so fan will come on with request of A/C?

 

[johnl455]

As far as AC ....request turns fan on low with the resistor in series that you DON'T Have When high side pressure rises it turns it on to high
Sounds like the aftermarket fan is wired to the high relay as the resistor setup probably went away with the OEM fan. Another reason not to hack the factory setup

 

[larry33kc]

Is the BS3 wired up to the AC? I no mine isnt which I might and might not do.

Does your idle bump up in RPM's when you put it in gear? Some guys wire it to that instead of the AC since BS3 only has the one circuit to bump idle which is the AC. HTH

 

[gnray76]

john---who said anything is hacked?? nothing has been hacked, I know how the system works, all wiring is there I'm not the one who removed the resistor, as stated above.. resistor was gone before the orig. took a shit! If you know the resistor removal procedure you would see nothing was hacked, just bypassed, and yes after market fan, No wiring was altered at all.

Larry-- not sure on the BS3, trying to figure out if there is a setting, have to put a call into, cause they cant answer a email over there, A/C engaged kicks RPM up, If I manually do the delay relay it works.. just don't engage through relay to come on when AC is turned on.. no my RPM idles down when in gear.

 

[larry33kc]

Ok, well if the goes up when you turn on the AC then it is wired to BS3. There is a screen that you can manualy turn things on but I don't remember what tab it is. Just look through the tab that has the configure screens in it I think it's in there some where it has alot of big blue dots in it. I will try to look when I get home.
Your best bet is to try to get ahold of Cal Hartline on this board he will help you.

 

[gnray76]

Thanks larry for the reply.. I looked around in there.. config. Has AC anticipates, IAC steps.. nothing for AC engaged. I think if not wrong the dash is were the dots are?
The wiring is all orig. Equipt. Just resistor was removed, so black n red tracer wire and black w pink tracer are placed together causing fan to be on high at all times. Just not when AC requested, idle kicks up turns on but no fan.... fan comes on when vehicle heats up to 165 then fans come on.

Posted from the TurboBuick.Com mobile app

 

[gnray76]

Placed a call into precision.. they said only time fan will come on is when fan settings in computer demand it to come on.. that I would have to wire in myself.. placed call into BS3 b4 hand,
but never spoke to tech, only lady up front who told me to call pete at precision..

Posted from the TurboBuick.Com mobile app

 

[RmvBfrFlght]

There should be a switch mounted to the A/C compressor or near it on the high pressure line. This will have three wires going to it. Once the A/C pressure is over 260 psi the switch activates the low speed fan relay. Once the A/C pressure is over 300 psi the switch activates the high speed fan relay.

The switch may be bad or the connector is unplugged. The three wires colors are:

DK GRN/YEL, DK GRN, and BLK/WHT

RemoveBeforeFlight

 

[pacecarta]

start here
http://vortexbuicks-etc.com/fan.htm

the high speed relay that should activate with AC on is controlled by the gray three wire switch on the ac line at rear of ac compressor

when theres pressure (AC system properly charged and ac clutch engaged ) it ground the green with yel stripe wire for the high speed relay and the fan will run

make sure that switch is installed and plugged in

 

[gnray76]

thanks all for replies
yes, if I ground the green w yellow tracer, does kick fan on.
printed wiring diagrams an all. going to read up on that article from pacecarta.
any other suggestions, please lmk
thanks again!!!

 

[RmvBfrFlght]

Try jumping the green/yellow wire to the black/white wire, this is within the connector. If the fan kicks on then the black/white wire going to ground is OK. In that case either the switch is bad or the A/C system is not working correctly (pressure too low).

RemoveBeforeFlight