AC Circuit Question.
08-20-2013, 06:04 PM
#16
Nordschleife Master
Thread Starter
this test is done with the wires connected to the switch.^^^^
If you have power on both sides of the freeze switch then its closed and may open when it gets cold .
SO you may have low pressure in the lines, THUS
the pressure switch at the receiver drier needs to be jumped.
this should allow power to go to the compressor.
NOTE there are 2 switches at the receiver drier one turns on the fan,
the other is the low pressure switch
NOTE dont run the compressor more than 20 seconds with low freon as it could seize due to no oil being circulated
If you have power on both sides of the freeze switch then its closed and may open when it gets cold .
SO you may have low pressure in the lines, THUS
the pressure switch at the receiver drier needs to be jumped.
this should allow power to go to the compressor.
NOTE there are 2 switches at the receiver drier one turns on the fan,
the other is the low pressure switch
NOTE dont run the compressor more than 20 seconds with low freon as it could seize due to no oil being circulated
08-20-2013, 06:16 PM
#17
On the other hand ...
The relay is not the only part of the circuit that gets stressed. When my AC clutch seized, the relay melted and one of the traces on the circuit board was weakened. That trace blew a few weeks after I installed the heavy duty Radio Shack relay on the AC controller and a new AC compressor.
Tired of that game, I decided to minimize demand on the AC controller and installed an external power relay, locating it on the inner fender well near the horns and the hot post.
Painless Performance sells a waterproof relay that integrates nicely.
Part number: 30130 Waterproof Fan Relay $ 57.01 (2010 price)
Just sayin'
The relay is not the only part of the circuit that gets stressed. When my AC clutch seized, the relay melted and one of the traces on the circuit board was weakened. That trace blew a few weeks after I installed the heavy duty Radio Shack relay on the AC controller and a new AC compressor.
Tired of that game, I decided to minimize demand on the AC controller and installed an external power relay, locating it on the inner fender well near the horns and the hot post.
Painless Performance sells a waterproof relay that integrates nicely.
Part number: 30130 Waterproof Fan Relay $ 57.01 (2010 price)
Just sayin'
08-20-2013, 07:43 PM
#18
Nordschleife Master
Thread Starter
Jump both the freeze and the low pressure switch and still no compressor engagement. Will go to the 14 pin next for evaluation.
I just want to get the compressor to go to fill though on the low pressure side.
08-20-2013, 08:06 PM
#19
Nordschleife Master
Thread Starter
Where do I go from here fellas ??
My next maneuver will be to check for voltage at the wire that feeds the 86 terminal on the secondary relay with the freeze AND the low pressure switch jumped.
08-20-2013, 08:22 PM
#21
Nordschleife Master
Thread Starter
I had split the wire when it exits the harness up front. The harness end feeds 86 of the new relay and the compressor end is tied in to the 87 terminus on the relay.
08-20-2013, 08:32 PM
#22
Team Owner
well you could go ahead and fill the system it by disconnecting the compressor wire by the dipstick tube,
then connecting a jumper to the compressor wire and hot post,
this will turn on the clutch.
run the engine and then fill the system ,.
disconnect the wire once its filled and troubleshoot the wires,
chances are you have miswired something if the parts your using are not stock
then connecting a jumper to the compressor wire and hot post,
this will turn on the clutch.
run the engine and then fill the system ,.
disconnect the wire once its filled and troubleshoot the wires,
chances are you have miswired something if the parts your using are not stock
08-20-2013, 08:55 PM
#23
Former Vendor
If I'm reading this correctly....
Remove your "second" relay. My rebuilt controller come with a much "studier" relay....and 100% of them get this new relay. If you need "more" relay than I installed in the rebuilt controller.....you have some severe electrical problems, with your A/C system.
Put everything back to stock.
Make sure the fuse that was sent with my rebuilt controller is installed on the double wire. going into the freeze switch....so you don't "melt" the new controller.
Turn on the ignition and the A/C.
Jump the A/C pressure switch.
Now you can measure voltages....remember this....write it down and hang it in your garage:
"Always test all vehicle electrical systems with "load" applied (the "consumer" turned on). Bad connections/flaws in an electrical systems can be "masked" by lack of load."
If you have 12 volts at that fuse attached to the freeze switch, but not 12 volts on the other side of the freeze switch (single yellow/blue wire).....the power is not getting through the freeze switch and it is bad.
Now it gets even more simple....there are only three possible outcomes:
Bypass the freeze switch by hooking the end of the fuse to the single yellow/blue wire (the fuse will be between the double wire and the single wire). If you now have power at the compressor and it engages....replace the freeze switch and move on. If the "fuse" blows....you have a short circuit (between here and the actual compressor....which is why you have a bad HVAC unit and a bad freeze switch.)
If you still have no power at the compressor....you have an open wire between the fuse and the compressor....or the coil inside the magnetic clutch is bad.
Remove your "second" relay. My rebuilt controller come with a much "studier" relay....and 100% of them get this new relay. If you need "more" relay than I installed in the rebuilt controller.....you have some severe electrical problems, with your A/C system.
Put everything back to stock.
Make sure the fuse that was sent with my rebuilt controller is installed on the double wire. going into the freeze switch....so you don't "melt" the new controller.
Turn on the ignition and the A/C.
Jump the A/C pressure switch.
Now you can measure voltages....remember this....write it down and hang it in your garage:
"Always test all vehicle electrical systems with "load" applied (the "consumer" turned on). Bad connections/flaws in an electrical systems can be "masked" by lack of load."
If you have 12 volts at that fuse attached to the freeze switch, but not 12 volts on the other side of the freeze switch (single yellow/blue wire).....the power is not getting through the freeze switch and it is bad.
Now it gets even more simple....there are only three possible outcomes:
Bypass the freeze switch by hooking the end of the fuse to the single yellow/blue wire (the fuse will be between the double wire and the single wire). If you now have power at the compressor and it engages....replace the freeze switch and move on. If the "fuse" blows....you have a short circuit (between here and the actual compressor....which is why you have a bad HVAC unit and a bad freeze switch.)
If you still have no power at the compressor....you have an open wire between the fuse and the compressor....or the coil inside the magnetic clutch is bad.
08-20-2013, 09:26 PM
#24
Team Owner
Glad you chimed in Greg,
I dont really know what the Op is up to with the relays and your rebuilt HVAC head unit.
But you know what they say a picture is worth a thousand words
I dont really know what the Op is up to with the relays and your rebuilt HVAC head unit.
But you know what they say a picture is worth a thousand words
08-20-2013, 11:30 PM
#25
Nordschleife Master
Thread Starter
Guys,
As seen in some past threads on chasing the Gremlin that would cause my compressor to cut off when the light switch was turned on to position 1 or 2, I have done some good diagnostic work to find the cause as a specific diode on Track 4 (ground track) of the hvac controller board. As my frail old relay was still working well, it was my intent to keep it that way by adding the secondary robust relay. It was also my intent to replace the diode. I began installing the hardware for the relay when the car was non driveable for I was doing fuel line and manifold work. The relay was already installed when I found I could not manage to desolder the old diode without disrupting the plastic infrastructure of the controller unit. Hence I left the relay and was simply going to plug Greg's unit into it. When Greg's unit arrived the wiring was already done. Explanation done.
Back to the current issue. This, I am embarrassed about.
Things didn't work as planned for I had plugged the 86 plug on the 87 spade, and vice versa. I knew all components were functional as they had been evaluated prior.
Will finish some late night work and have cold AC with my lights on for a hot humid New England day tomorrow.
Thanks to all for your suggestions and input.
Kindly Again,
Craig
As seen in some past threads on chasing the Gremlin that would cause my compressor to cut off when the light switch was turned on to position 1 or 2, I have done some good diagnostic work to find the cause as a specific diode on Track 4 (ground track) of the hvac controller board. As my frail old relay was still working well, it was my intent to keep it that way by adding the secondary robust relay. It was also my intent to replace the diode. I began installing the hardware for the relay when the car was non driveable for I was doing fuel line and manifold work. The relay was already installed when I found I could not manage to desolder the old diode without disrupting the plastic infrastructure of the controller unit. Hence I left the relay and was simply going to plug Greg's unit into it. When Greg's unit arrived the wiring was already done. Explanation done.
Back to the current issue. This, I am embarrassed about.
Things didn't work as planned for I had plugged the 86 plug on the 87 spade, and vice versa. I knew all components were functional as they had been evaluated prior.
Will finish some late night work and have cold AC with my lights on for a hot humid New England day tomorrow.
Thanks to all for your suggestions and input.
Kindly Again,
Craig
Last edited by MainePorsche; 08-21-2013 at 02:59 AM. Reason: 'With to without'
08-20-2013, 11:42 PM
#26
Former Vendor
Guys,
As seen in some past threads on chasing the Gremlin that would cause my compressor to cut off when the light switch was turned on to position 1 or 2, I have done some good diagnostic work to find the cause as a specific diode on Track 4 (ground track) of the hvac controller board. As my frail old relay was still working well, it was my intent to keep it that way by adding the secondary robust relay. It was also my intent to replace the diode. I began installing the hardware for the relay when the car was non driveable for I was doing fuel line and manifold work. The relay was already installed when I found I could not manage to desolder the old diode with disrupting the plastic infrastructure of the controller unit. Hence I left the relay and was simply going to plug Greg's unit into it. When Greg's unit arrived the wiring was already done. Explanation done.
Back to the current issue. This, I am embarrassed about.
Things didn't work as planned for I had plugged the 86 plug on the 87 spade, and vice versa. I knew all components were functional as they had been evaluated prior.
Will finish some late night work and have cold AC with my lights on for a hot humid New England day tomorrow.
Thanks to all for you suggestions and input.
Kindly Again,
Craig
As seen in some past threads on chasing the Gremlin that would cause my compressor to cut off when the light switch was turned on to position 1 or 2, I have done some good diagnostic work to find the cause as a specific diode on Track 4 (ground track) of the hvac controller board. As my frail old relay was still working well, it was my intent to keep it that way by adding the secondary robust relay. It was also my intent to replace the diode. I began installing the hardware for the relay when the car was non driveable for I was doing fuel line and manifold work. The relay was already installed when I found I could not manage to desolder the old diode with disrupting the plastic infrastructure of the controller unit. Hence I left the relay and was simply going to plug Greg's unit into it. When Greg's unit arrived the wiring was already done. Explanation done.
Back to the current issue. This, I am embarrassed about.
Things didn't work as planned for I had plugged the 86 plug on the 87 spade, and vice versa. I knew all components were functional as they had been evaluated prior.
Will finish some late night work and have cold AC with my lights on for a hot humid New England day tomorrow.
Thanks to all for you suggestions and input.
Kindly Again,
Craig
Install "my" the fuse at the freeze switch. And add an 8 amp fuse on 30 of your new relay.....all will be fine.
08-20-2013, 11:49 PM
#27
Nordschleife Master
Thread Starter
Appreciate it.
I already had 3 amp fuse on the freeze switch, and have a 10 amp fuse on the 30.
09-01-2013, 12:28 AM
#29
So before all these other steps one can jump the ac compressor wire to 12v to see if the clutch engages, correct?
09-01-2013, 12:40 AM
#30
Nordschleife Master
Thread Starter