How to test a relay?
10-09-2010, 10:01 AM
#61
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Re: How to test a relay?
Well, it's not the push button unit, it's not the relay, it's not the low pressure switch. Also, now the defogger flaps don't want to close when they should. there's no leak in the vacuum element that closes them, it tries to close them, but it just doesn't pull the flap quite enough to close it.
I'm just going to go kill myself I think.
Ok, well I think the reason I'm not getting enough closure on the defogger flaps nor any opening on the center flaps is there's a check valve involved that is in the line for both of those. Still don't understand the A/C. Fuck it, I'm just going to take it to a shop.
I'm just going to go kill myself I think.
Ok, well I think the reason I'm not getting enough closure on the defogger flaps nor any opening on the center flaps is there's a check valve involved that is in the line for both of those. Still don't understand the A/C. Fuck it, I'm just going to take it to a shop.
Last edited by marlinspike; 10-09-2010 at 10:51 AM.
10-10-2010, 05:01 PM
#63
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Re: How to test a relay?
Where you at? For the time being, my dash is still apart because while I didn't figure out the A/C I did figure out two other problems (when air is supposed to go to center vents it keeps switching to defogger vents because of a bad switch valve, and thermostat is slow to respond because the fan that pulls air for it is dead) and I don't want to put it back together until I get the parts in.
I'm starting to think it might be the low pressure switch, but shouldn't jumping the switch engage the clutch if that were the case? Jumping the switch does turn on the aux fan (i.e. the fan in front of the a/c rad, as opposed to the engine fan).
I'm starting to think it might be the low pressure switch, but shouldn't jumping the switch engage the clutch if that were the case? Jumping the switch does turn on the aux fan (i.e. the fan in front of the a/c rad, as opposed to the engine fan).
10-10-2010, 05:32 PM
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Re: How to test a relay?
Williamston, NC.
As for jumping it, depends on the design. If it's simply a low-pressure switch (2-wire) that should, in theory, work.
If it's a 3-wire, then forget it.
Best way to see though - find the A/C Clutch Relay, and jump pin 30 to 87. Should blow cold in the car. That's an auto on for the A/C. If it's not cold, then you will need to consider hooking up gauges and seeing if the pressure is low, or if it's high. (Both will cause it not to cool.) Low means you're out of freon, and then of course, the low pressure switch would be accurate, not broke. High would generally indicate a problem with airflow through the condenser, or a restriction in the system. If both sides are equal, and about 80-90 psi, then the compressor isn't on....
There's a lot of stuff to it, and troubleshooting it, but it goes rather quickly when you're used to doing it!
Start by figuring out which 2 pins are 12V in, and 12V to compressor clutch, (At the Relay) and jump those 2 with a jumper wire, bypassing the relay.
That will tell us if there's a mechanical issue with the A/C, or if it's simply electrical.
Incidentally, may be up your way this coming weekend.
As for jumping it, depends on the design. If it's simply a low-pressure switch (2-wire) that should, in theory, work.
If it's a 3-wire, then forget it.
Best way to see though - find the A/C Clutch Relay, and jump pin 30 to 87. Should blow cold in the car. That's an auto on for the A/C. If it's not cold, then you will need to consider hooking up gauges and seeing if the pressure is low, or if it's high. (Both will cause it not to cool.) Low means you're out of freon, and then of course, the low pressure switch would be accurate, not broke. High would generally indicate a problem with airflow through the condenser, or a restriction in the system. If both sides are equal, and about 80-90 psi, then the compressor isn't on....
There's a lot of stuff to it, and troubleshooting it, but it goes rather quickly when you're used to doing it!
Start by figuring out which 2 pins are 12V in, and 12V to compressor clutch, (At the Relay) and jump those 2 with a jumper wire, bypassing the relay.
That will tell us if there's a mechanical issue with the A/C, or if it's simply electrical.
Incidentally, may be up your way this coming weekend.
Last edited by BAD4DR; 10-10-2010 at 05:37 PM.
10-10-2010, 05:57 PM
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Re: How to test a relay?
Williamston, NC.
As for jumping it, depends on the design. If it's simply a low-pressure switch (2-wire) that should, in theory, work.
If it's a 3-wire, then forget it.
Best way to see though - find the A/C Clutch Relay, and jump pin 30 to 87. Should blow cold in the car. That's an auto on for the A/C. If it's not cold, then you will need to consider hooking up gauges and seeing if the pressure is low, or if it's high. (Both will cause it not to cool.) Low means you're out of freon, and then of course, the low pressure switch would be accurate, not broke. High would generally indicate a problem with airflow through the condenser, or a restriction in the system. If both sides are equal, and about 80-90 psi, then the compressor isn't on....
There's a lot of stuff to it, and troubleshooting it, but it goes rather quickly when you're used to doing it!
Start by figuring out which 2 pins are 12V in, and 12V to compressor clutch, (At the Relay) and jump those 2 with a jumper wire, bypassing the relay.
That will tell us if there's a mechanical issue with the A/C, or if it's simply electrical.
Incidentally, may be up your way this coming weekend.
As for jumping it, depends on the design. If it's simply a low-pressure switch (2-wire) that should, in theory, work.
If it's a 3-wire, then forget it.
Best way to see though - find the A/C Clutch Relay, and jump pin 30 to 87. Should blow cold in the car. That's an auto on for the A/C. If it's not cold, then you will need to consider hooking up gauges and seeing if the pressure is low, or if it's high. (Both will cause it not to cool.) Low means you're out of freon, and then of course, the low pressure switch would be accurate, not broke. High would generally indicate a problem with airflow through the condenser, or a restriction in the system. If both sides are equal, and about 80-90 psi, then the compressor isn't on....
There's a lot of stuff to it, and troubleshooting it, but it goes rather quickly when you're used to doing it!
Start by figuring out which 2 pins are 12V in, and 12V to compressor clutch, (At the Relay) and jump those 2 with a jumper wire, bypassing the relay.
That will tell us if there's a mechanical issue with the A/C, or if it's simply electrical.
Incidentally, may be up your way this coming weekend.
That said, when I tried jumping that along with the low pressure switch (which is a 2 wire switch, I jumped it to get the aux fan on), I didn't get cold air; however, at the time my push button unit was being buggy, which is no longer the case, so I'll try it against tomorrow. I would say this is a pretty good sign the pressure is wrong, except that it still doesn't explain why jumping the low pressure switch wires doesn't engage the clutch.
Last edited by marlinspike; 10-10-2010 at 06:00 PM.
10-11-2010, 09:09 AM
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Re: How to test a relay?
Wow, I am such an idiot. The thing I was jumping wasn't the low pressure switch but the temperature switch which is also on the drier. Jumped the low pressure switch and the clutch engaged...so...either I have low pressure or I have a bad switch.
On the other hand, it's good that I'm an idiot, because it gave me the motivation to dig around and figure out why my HVAC temp sensor responds slowly and why my vents don't always do what they should, and to finally spend the money for a push button unit that has buttons that will stay in.
On the other hand, it's good that I'm an idiot, because it gave me the motivation to dig around and figure out why my HVAC temp sensor responds slowly and why my vents don't always do what they should, and to finally spend the money for a push button unit that has buttons that will stay in.
Last edited by marlinspike; 10-11-2010 at 09:15 AM.