A/C Failure! Any guesses?
04-27-2004, 08:49 AM
#16
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Who? 
nah, we have very VERY few patrol cars roaming around the highway. Unlike in the USA, our radars are Fixed on the highway (so, just remember where they are). But there are the small portable ones laying around on the beach or in town. Well, like my profile says, the car is lowered from the stock 4.72' (more or less) in ground clearance to 3.7 (more or less again) and the only debris here are mountains otherwise known as stupid huge humps for now reason. But the STANDARD hump size here is 2", so just as long as i don't go on the hump too fast, things should be ok.
nah, we have very VERY few patrol cars roaming around the highway. Unlike in the USA, our radars are Fixed on the highway (so, just remember where they are). But there are the small portable ones laying around on the beach or in town. Well, like my profile says, the car is lowered from the stock 4.72' (more or less) in ground clearance to 3.7 (more or less again) and the only debris here are mountains otherwise known as stupid huge humps for now reason. But the STANDARD hump size here is 2", so just as long as i don't go on the hump too fast, things should be ok.
04-27-2004, 08:54 AM
#17
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yeah flyguy, I've got the same thing happening here too - it blows the fuse as soon as the a/c is turned on.
The a/c didn't work when I got the car, took it to the local porsche guys, who sublet the a/c work out to someone else. They just did some basic a/c maintenance type work and the a/c started working again. Which is funny because the previous owner was convinced that the compressor had gone.
So I took the car up the coast once I got the car back, had the A/C on the whole way but it died about 8/10s of the way into the trip (about 1-2 hrs of use). Now the fuse fries every time I turn the a/c on, and I get hot air coming out of the vents (I thought I was going to get burns on my feet on the long trip back home!)
None of this really concerns me that much though, I don't mind driving with the windows down, I can hear the music of the engine better
The a/c didn't work when I got the car, took it to the local porsche guys, who sublet the a/c work out to someone else. They just did some basic a/c maintenance type work and the a/c started working again. Which is funny because the previous owner was convinced that the compressor had gone.
So I took the car up the coast once I got the car back, had the A/C on the whole way but it died about 8/10s of the way into the trip (about 1-2 hrs of use). Now the fuse fries every time I turn the a/c on, and I get hot air coming out of the vents (I thought I was going to get burns on my feet on the long trip back home!)
None of this really concerns me that much though, I don't mind driving with the windows down, I can hear the music of the engine better
04-27-2004, 10:42 AM
#18
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But if your fuse keeps on blowing everytime, that indicated an electrical problem. First of all, are you using the same fuse? ie is the fuse is 20 or 30amp you are placing in the right fuse? if yes, then did you try installing a higher amp fuse? ie if the fuse is 30, try placing a 40amp fuse instead. If that fuse STILL blows, then for sure that there is an electrical shortage somewhere.....am i right?
04-27-2004, 11:07 AM
#19
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IIRC the fuse is suppose to be a 7.5 amp. In the winter when my heat didn't work (same fuse) I put in a 10 amp (or whatever the next size up was). That worked great until I used th AC, then it blew again. I agree that it is most likely an electrical problem. The thing is it seems to be a fairly common problem too. It might just be the 18 year old wires running everywhere, or something like that. I think finding that might be next weekend's job for me. I've got a number of other electrical issues to tackle then anyways.
04-27-2004, 12:18 PM
#20
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Skene et al,
I'm going through the AC fuse failure wire by wire right now, trying to see where the problem is. At first, I thought I had it figured out, but followed a red herring. if you find something before I do, let me know... I'll be working as much as I can for the next few days as I start my new job on Monday.
I'll keep posting on this thread as I narrow things down.
-Ian
I'm going through the AC fuse failure wire by wire right now, trying to see where the problem is. At first, I thought I had it figured out, but followed a red herring. if you find something before I do, let me know... I'll be working as much as I can for the next few days as I start my new job on Monday.
I'll keep posting on this thread as I narrow things down.
-Ian
04-27-2004, 12:41 PM
#21
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Guys... LISTEN VERY CLOSELY!!
The reason the fuse is blowing is that the current draw for the compressor clutch is exceeding 7.5amps (the fuse size). This means the clutch is on it's way out (most likely).
DO NOT... UNDER ANY CIRCUMSTANCES, REPLACE THE 7.5 AMP WITH A HIGHER ONE.
You will roast the control unit (it may even catch fire!) Ask me how I know!
I found the easiest solution was to replace the compressor with a rebuilt one. Converted to R134 at the same time, and one year later, all's still well....
The reason the fuse is blowing is that the current draw for the compressor clutch is exceeding 7.5amps (the fuse size). This means the clutch is on it's way out (most likely).
DO NOT... UNDER ANY CIRCUMSTANCES, REPLACE THE 7.5 AMP WITH A HIGHER ONE.
You will roast the control unit (it may even catch fire!) Ask me how I know!
I found the easiest solution was to replace the compressor with a rebuilt one. Converted to R134 at the same time, and one year later, all's still well....
04-27-2004, 01:32 PM
#22
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Originally posted by RPG951S
Guys... LISTEN VERY CLOSELY!!
The reason the fuse is blowing is that the current draw for the compressor clutch is exceeding 7.5amps (the fuse size). This means the clutch is on it's way out (most likely).
DO NOT... UNDER ANY CIRCUMSTANCES, REPLACE THE 7.5 AMP WITH A HIGHER ONE.
You will roast the control unit (it may even catch fire!) Ask me how I know!
I found the easiest solution was to replace the compressor with a rebuilt one. Converted to R134 at the same time, and one year later, all's still well....
Guys... LISTEN VERY CLOSELY!!
The reason the fuse is blowing is that the current draw for the compressor clutch is exceeding 7.5amps (the fuse size). This means the clutch is on it's way out (most likely).
DO NOT... UNDER ANY CIRCUMSTANCES, REPLACE THE 7.5 AMP WITH A HIGHER ONE.
You will roast the control unit (it may even catch fire!) Ask me how I know!
I found the easiest solution was to replace the compressor with a rebuilt one. Converted to R134 at the same time, and one year later, all's still well....
AGREE: you should not use a higher fuse unless you remove the temp unit to jump pins A8/B2 (same as hitting the defrost or AC button)
DISAGREE: it may not be the compressor... I know because I have a new compressor AND clutch in the car and it still blows the fuse... 20 amp one i might add (AGAIN DONT USE THE HIGHER FUSE WITH THE TEMP UNIT IN PLACE!!!)
For those of you familiar with the AC system, the wiring diagram shows a "6 pin plug" coming off the temp unit that harnesses several of the AC/Heating wires together. Anyone know where this plug is?
Also, I'm looking for the Icing Protection sensor. I'm guessing it's at the coils, however is there a way to unhook this sensor without dismantling the blower assembly in front of the windshield?
this gremlin is leading me quickly to
-Ian
04-28-2004, 04:54 PM
#23
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GOT IT!!!
well, mine at least.
Seems that it IS the clutch / compressor after all. Since it's not the original or even OEM unit, that should have been expected. Basically, the old one was toast either way. So when I put in a new one, my mechanic suggested a standard compressor that someone had made aluminum bolt on brackets for to bolt up to the original mounting points.
well, the new clutch pulls LOTS of power (somewhere between 10 and 15 amps) to engage, but once engaged, pulls almost nothing - hence the fuse blowing. I fixed the problem by using the stock wiring to power a $4 relay from Radio shack that has a dedicated 12ga wire ($2.15) running direct from the Battery +12 to it to the compressor. There's an inline fuse in the assembly ($3.00) which I mounted inside a small tupperware type container ($2.50) below the 'snorkel' behind the drivers side headlight. Including connectors, the project cost me about $15.
If anyone wants more details, lemme know. Eventually, I'll do the same type of setup to fix the fact that i only get 9.5 volts to my headlights... it'll be nice to see the deer again - or possums as we have down here in Dallas.
-Cheers,
Ian
well, mine at least.
Seems that it IS the clutch / compressor after all. Since it's not the original or even OEM unit, that should have been expected. Basically, the old one was toast either way. So when I put in a new one, my mechanic suggested a standard compressor that someone had made aluminum bolt on brackets for to bolt up to the original mounting points.
well, the new clutch pulls LOTS of power (somewhere between 10 and 15 amps) to engage, but once engaged, pulls almost nothing - hence the fuse blowing. I fixed the problem by using the stock wiring to power a $4 relay from Radio shack that has a dedicated 12ga wire ($2.15) running direct from the Battery +12 to it to the compressor. There's an inline fuse in the assembly ($3.00) which I mounted inside a small tupperware type container ($2.50) below the 'snorkel' behind the drivers side headlight. Including connectors, the project cost me about $15.
If anyone wants more details, lemme know. Eventually, I'll do the same type of setup to fix the fact that i only get 9.5 volts to my headlights... it'll be nice to see the deer again - or possums as we have down here in Dallas.
-Cheers,
Ian
04-28-2004, 05:25 PM
#24
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Glad you fixed your problem Ian! And thanks for the tip Raagi. It looks like I won't be able to get to this for a little while as more pressing matters have come up, one of which being the headlight bit Ian wants to do. For that I think I'm going to go ahead and get a wireing kit from IceShark. It's not cheap, but a whole lot easier then getting everything together myself and wireing it up.
One other question, what and where is the temp unit you're talking about? I'm currently running a higher amp fuse, mainly because I ran out of 7.5 amp ones and havn't gotten more yet, and don't want to do too much damage to what's in there.
When I get a chance to, I'll check out my compresser to see if it's pulling too much. Would low freeon cause this? or is it more serious then that?
One other question, what and where is the temp unit you're talking about? I'm currently running a higher amp fuse, mainly because I ran out of 7.5 amp ones and havn't gotten more yet, and don't want to do too much damage to what's in there.
When I get a chance to, I'll check out my compresser to see if it's pulling too much. Would low freeon cause this? or is it more serious then that?
05-03-2004, 09:02 PM
#25
Instructor
ok... just closing my end of this thread.
here's what I ended up doing... ok, not the best looking fix, but it works, and for now that'll have to do... eventually, I will probably hide the relay inside the fender so that it cant be seen without really looking.
The thick black wire on the right is a direct line from the battery (12 gauge) and the fuse is a 15 amp inline fuse BEFORE the relay. the relay is rated to 30, but I figured I'd protect it anyway. In reality, I should have probably put the fuse on the other end of the line up at the battery itself.
the thin black wire going behind the evaporator canister is the wire from the original wiring harness end to the relay. the green is from the relay out to ground.
the thick black wire on the left behind the evaporator is the switched power to the compressor (12 gauge).
All of the original safeties of the system are kept functional (low pressure switch and icing protection)
write with any questions.
-Ian
here's what I ended up doing... ok, not the best looking fix, but it works, and for now that'll have to do... eventually, I will probably hide the relay inside the fender so that it cant be seen without really looking.
The thick black wire on the right is a direct line from the battery (12 gauge) and the fuse is a 15 amp inline fuse BEFORE the relay. the relay is rated to 30, but I figured I'd protect it anyway. In reality, I should have probably put the fuse on the other end of the line up at the battery itself.
the thin black wire going behind the evaporator canister is the wire from the original wiring harness end to the relay. the green is from the relay out to ground.
the thick black wire on the left behind the evaporator is the switched power to the compressor (12 gauge).
All of the original safeties of the system are kept functional (low pressure switch and icing protection)
write with any questions.
-Ian
