Intermittent A/C Failure

[VBRoamer]

97 LX450 a/c fan stops every once in a while, so no a/c. Fan belt is there. Freon checks out. What are the likely causes?

I've thought of:
* fan clutch
* buttons in dash
* wire connections
* wiring

I actually don't know what I'm talking about so apologies if any of these possibilities make no sense.

 

[jonheld]

To be clear, are you referring to the cabin blower fan for HVAC?
By "stops once in a while" do you mean no air blowing out of the vents on the dash?
If so, that has nothing to do with engine cooling.

 

[iptman]

You got an OBD2 scanner (ScanGauge or the like)? 80s will shut off AC at 227* (if I recall) so maybe it's getting hot and you're not realizing?

Edit: I think just the compressor kicks off when this happens, not the fan. Carry on...

 

[Crusha]

Vince, does the blower motor operate on all speeds?

 

[TheMU]

97 LX450 a/c fan stops every once in a while, so no a/c. Fan belt is there. Freon checks out. What are the likely causes?

I've thought of:
* fan clutch
* buttons in dash
* wire connections
* wiring

I actually don't know what I'm talking about so apologies if any of these possibilities make no sense.

Vince,

I think there is a relay as well IIRC.
The 80s have an ambient air sensor in the front bumper as well.

 

[VBRoamer]

To be clear, are you referring to the cabin blower fan for HVAC?
By "stops once in a while" do you mean no air blowing out of the vents on the dash?
If so, that has nothing to do with engine cooling.

Cabin blower
No air blowing

 

[VBRoamer]

You got an OBD2 scanner (ScanGauge or the like)? 80s will shut off AC at 227* (if I recall) so maybe it's getting hot and you're not realizing?

Edit: I think just the compressor kicks off when this happens, not the fan. Carry on...

Not a 227+ issue. Have temp on scan gauge to read. Know the situation: crossing Kansas, 115 degree temp, 70 mph, it quits blowing cold

 

[VBRoamer]

Vince, does the blower motor operate on all speeds?

When it runs, it does operate at each speed setting

 

[VBRoamer]

Vince,

I think there is a relay as well IIRC.
The 80s have an ambient air sensor in the front bumper as well.

Where is the relay?

 

[TheMU]

Where is the relay?

Vince, if memory serves me right, its in the engine bay.

 

[jonheld]

Vince, if memory serves me right, its in the engine bay.

Negative. The heater relay activates the cabin fan. It lives in the driver's side kick panel.
The A/C amplifier in the dash controls the heater relay as well as the entire system.

 

[TheMU]

I was under the impression the "CDS Fan" was HVAC related.
CDS meaning condensor.

My HDJ81 does not have this feature.

 

[jonheld]

I was under the impression the "CDS Fan" was HVAC related.
CDS meaning condensor.

The CDS fan and associated circuit was for certain markets. The US spec 80s never got these, with a host of other goodies that we missed out on.
It is an aux fan that is mounted on the US passenger side of the condenser and fires according to the AC pressure switch IIRC.