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Intermittent blower fan on '73 Calais

Started by Nashville Native, August 12, 2015, 10:08:08 PM

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Nashville Native

After replacing the compressor and installing a receiver/dryer upgrade kit, I've got cold A/C in my '73 Calais sedan with climate control. Some of the time. The blower fan comes on when it wants to, turns off when it wants to, regardless of whether the switch is in the Low, Auto, or High position. Cleaned all the electrical contacts and it worked consistently for three days, then went back to being intermittent.

Suggestions?
1973 Calais sedan http://bit.ly/1Qf0Bta RIP

TJ Hopland

Does it stay running steady on DEF?  It should.   DEF is pretty much a direct route to fan high.   Other modes depend on various sensors and other stages of the control system.    If its not running steady on DEF I would be looking for connection issues.   The blower is fairly high current so it only takes a slightly loose connector to start arching.   

Upgrade kit?  To repair the VIR or did you get a VIR eliminator kit?
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Julien Abrahams

Also, check all vacuum connections, especially the ones that go to the main switch. If there is a vacuum leak somewhere, this sort of behavior can occur.
1954 Cadillac series 62
1967 Cadillac Sedan De Ville HT
1969 Austin Healey Sprite
1979 Opel Kadett

Scot Minesinger

If the fan cycles from low to med to high on it's own when it is working then you know it is not the programmer behind glove box.  If the programmer is bad fan will be on high all the time.

Sounds like you have a bad fan relay (there are two, and those are inexpensive, like $10 each) on fire wall, or it could be your dash switch with temperature wheel.  Cadillac Tim and others sell rebuilt dash units.

Should add that it could be your blower motor.  These are inexpensive too, and you could replace it as a precaution to rule that out, as these intermittent electrical problems are difficult to track down.  In the past it has been either the fan motor or dash unit when this happens to me.

Good luck,

Scot
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

"Cadillac Kid" Greg Surfas 15364

I second TJ's question, What is a receiver/dryer upgrade kit?
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Scot Minesinger

Yes, everyone is interested in if you replaced the VIR with something different that serves the triple function formerly managed by the drier, expansion valve and POA in 1972, or you rebuilt VIR.   
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

Nashville Native

Quote from: TJ Hopland on August 12, 2015, 11:40:26 PM
Does it stay running steady on DEF?  It should.   DEF is pretty much a direct route to fan high.   Other modes depend on various sensors and other stages of the control system.    If its not running steady on DEF I would be looking for connection issues.   The blower is fairly high current so it only takes a slightly loose connector to start arching.   
Finally got my car back from having a bunch of transmission leaks fixed. The fan quit for a bit when I was driving to work and when I switched it to DEF, it came back on. Switched it back to AUTO and it went off again, left it there and after a few minutes, it came back on again by itself, as it was doing before.

So in other words, the fan will work on DEF, but is intermittent in other modes.

QuoteUpgrade kit?  To repair the VIR or did you get a VIR eliminator kit?
I'll have to ask the shop. I think they got parts from Old Air Products.
1973 Calais sedan http://bit.ly/1Qf0Bta RIP

Scot Minesinger

Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

TJ Hopland

The area Scott is interested in is the firewall area under the hood where the AC hoses go in.   We are interested in what sort of canisters and such are there.     If they got it from Old Air I bet its the same kit I got.

My brain and memory is not working at the moment and I don't know where my manual or Tim's book is so I can't help much on what the next troubleshooting step will be for the blower but I think working on DEF means the basic circuit is fine, its a control issue.  I remember the the DEF mode the blower relay gets a ground direct from the slide switch lever.   Other modes the relay ground gets routed through other switches and sensors like in heat mode it has to come from the sensor behind the alternator.  I don't remember where it comes from for cool modes but I think it has to do with some temp sensors so what may be happening is what ever routes that ground between heat and cool may not be working. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Nashville Native

1973 Calais sedan http://bit.ly/1Qf0Bta RIP

Scot Minesinger

This kit can harm your compressor during the boarder line temps in spring and fall.

This VIR elimination kit is fine when it is real hot outside.  When you put it in auto and it is cooler, the compressor will be cycled on and off with the green wires making and unmaking based on refrigerant pressure.  You can hear the clutch cycle on and off.  When it is 55'F outside and sunny a/c will be needed on the highway.  However in the shade it will not. 

Park the car in the shade when it is 55'f outside, set car to auto and 72'F and open the hood.  You will hear the a/c clutch engage and disengage very frequently.  In my garage this happens like 30 times a minute.  If this happens on the highway your compressor will not last long.

I would go back to the VIR, or for the time being turn a/c on only when real hot outside.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

"Cadillac Kid" Greg Surfas 15364

All comments about the conversion or R-134a aside, I would look into the possibility that the installers routed the ATC feed throught the new temperature/pressure switch instead of just the compressor clutch.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Nashville Native

We'll be getting into the mild temperatures soon, so I'll go back to cruising around with the windows down. But what about the winter? Doesn't the climate control use the A/C compressor when supplying heat to the cabin?
1973 Calais sedan http://bit.ly/1Qf0Bta RIP

"Cadillac Kid" Greg Surfas 15364

The real question is, what actually works on your system and what was modified in the controls when they did the VIR/bypass conversion?
In your original system with the VIR, the compressor ran all the time, the TX valve capsule in the VIR fed refrigerant to the evaporator and the POA Capsule in the VIR kept the evaporator temperature at (ca.) 35 degrees F.  That way the Automatic Temperature Control (ATC) system could cool and dehumidify ALL the air and then reheat it over the heater coil as required to deliver air to the cabin at the correct temperature to provide the cooling or heating as "requested" by the temperature control dial. 
All that said, I would go back to the shop that did the conversion and be sure they connected the VIR bypass switch to the compressor clutch circuit and not to any of the main ATC circuitry.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Scot Minesinger

That is why the original VIR is best to just keep it working as intended.  The replacement unit has the ability to turn something off electrically (the continuity between green wires is broken when suction pressure is too low) rather than mechanically manage the suction pressure to keep it from getting too low.  The VIR eliminator is not free and the cost to re-build the VIR is likely comparable.  The VIR does a nice job on air conditioning with r134.  I have converted half a dozen Cadillacs with VIR to r134 and most complain (in a complimentary way) that the a/c will drive you out of there.  I just don't get the benefit of the VIR eliminator kit, especially if miss applied to cycle compressor clutch, it is likely to ruin the compressor.  It does not make air colder, it is not less costly, and it costs you in judging - why do it? 

BTW the original post was on the blower fan, is it running now?
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

Nashville Native

I drove the car on an errand yesterday, just in the neighborhood. The fan worked the whole time. I'll drive it to work again tomorrow and see if quits or not. I've yet to find a bad connection, but I've barely had a chance to look.

As for "why", I just wanted to get A/C on the car as soon as I could. Didn't realize it would cost me at a CLC event. Hadn't planned on entering for a few years, as the paint has faded to a matte green, and the interior could use new cloth inserts.
1973 Calais sedan http://bit.ly/1Qf0Bta RIP

Scot Minesinger

The authenticity aside the main issue is your compressor can easily be damaged starting and stopping 30 times a minute on the highway when it is 50'F with VIR eliminator.  Rebuilt VIR valves are readily available, you can order one today and have it next day.  Best to only enable a/c on hot days.  Since VIR valves are available, I really don't know why a VIR eliminator is even offered, it cannot be much cheaper?
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

Nashville Native

Quote from: Scot Minesinger on August 19, 2015, 08:48:58 PM
The authenticity aside the main issue is your compressor can easily be damaged starting and stopping 30 times a minute on the highway when it is 50'F with VIR eliminator.  Rebuilt VIR valves are readily available, you can order one today and have it next day.  Best to only enable a/c on hot days.  Since VIR valves are available, I really don't know why a VIR eliminator is even offered, it cannot be much cheaper?
I dunno. I'm still new to the classic Cadillac world. BTW, when it's 50'F, I'm going to have the heater on. Will I have heat? Or is that when the compressor will be starting and stopping?
1973 Calais sedan http://bit.ly/1Qf0Bta RIP

Scot Minesinger

You don't need the compressor for heat.  If it was 50'F outside in 1973 and the car was in auto set to 72'F the compressor would be running.  Just make sure compressor is not running when it is not hot outside.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

TJ Hopland

I got the same system on my 73 and the compressor does not seem to cycle 30 times in a minute when its cool outside, it cycles about the same as my 80's cars do.   One thing that appears to be different about mine than some other is I do not have the original A6 compressor, mine is an aftermarket Sanden so maybe that is why mine seems to operate like an 80's system?

My memory has not been the best the last couple years but on mine I remember doing something with the wires on the heater box, I think it had to do with the thermal fuse.  In the photo it does not look like they did anything at least on that side of the wiring, maybe the did tap into it but on the other side of the ac box?   Can you see where the wires on that pressure switch go?  Again I don't remember the details and maybe mine was different due to the different compressor but looking at my photo it looks like I moved wires from the thermal switch to the new low pressure switch.   I think I also have a high pressure switch on the line between the condenser and evaporator.  That switch may also have a thermal component in it or I may have something like that elsewhere in the circuit.  I had forgot about it but after reading Scott's anti eliminator speech again I sort of remember the shop I had make the hoses mention that I needed something to keep it from running when it was too cold.   I just remember buying what ever the shop told me I should have.    My fuzzy memory thinks I ran the original compressor clutch wire to the high pressure switch and then a new wire from that switch to the clutch.   I don't have that car where I am at now but if you are not getting anywhere I can take a peek at it and refresh my memory and try and get my brain turned on. 



StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason