8 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHAnother AC problem thread
Leading reported evidence
Replace a/c compressor
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
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Discussions that performed work without a confirmed outcome
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Performed · outcome unconfirmed · Original poster
I have jumped the switchs and relays, and I replaced the A/C compressor.
Leading evidence: 'Replace a/c compressor' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'power side not the trigger, although u need' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Check 12v at the compessor' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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1
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Suspected cause
I think your issue is the power side not the trigger, although u need to check those wires to be sure.
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
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Suggestion
Im betting u have a relay or wiring issue but u need to check eveything.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
8 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T122219Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Hey guys!
Long time reader, first time poster. I'm doing some work on our 996 C2 Cabrio we got a while back. We got it for a "good deal" from a guy in Phoenix because it had some issues that he no longer wanted to chase. After getting the car running with a new DME and Immobilizer, we started tackling some of the other issues we knew the car had. The convertible top is just about complete, with a lot of help from members of this forum. Now we're on to the A/C system, and what a nightmare this has been. I've read just about every thread out there, and still can't bring it back around to the issues we are having. Let's get into it!
The A/C compressor clutch wouldn't engage. Using a Durametric, I tried activating it with no success, and also no codes. This led me to believe that the compressor itself was bad. After swapping it out, I still didn't have any luck getting the compressor to spin. The snowflake on the display lights up, which indicates to me that the control is functioning properly. I went to jump the pressure switch on the fill port under the frunk, and got the front fans to kick on, but still no compressor. Then we tried jumping 87 and 30 on the A/C relay, still no avail! I plugged the Durametric back in and got code 30 - AC Handling Fault. With no idea what that means, I feel like I'm back at square one.
On one of the 993 forums I came across, someone had mentioned on that car that the fog light and back up light relay was tied to the 12v supply of the AC Compressor. We noticed that the reverse lights do not work, and that led me on a goose chase for a similar relay in my 996. While digging through relays and fuses, I came across fuse D6, a 30 amper that was completely melted. I've never seen anything like it. I pulled it to replace it and realized the blower fan also kicks off. The same thing happens when I pull E7 which helps me determine the fuses and power to the block are fine.
With all of this said, I am completely stumped. I have it charged up with about 20oz of r134, as much as I can get in without the compressor kicking on. I have jumped the switchs and relays, and I replaced the A/C compressor. What else should I be looking for? I'm really not wanting to gut the harness, but I feel like that's my only option. All of your help is greatly appreciated!
Have u checked for 12v at the compessor? If not u need to get the wiring diagram and work your way backward through the relays and fuses. Checking for continuity and your grounds. I doubt its a triger signal issue since the durametric doesnt triger it. Im betting u have a relay or wiring issue but u need to check eveything.
Thank you for the reply. I haven't checked 12v at the compressor, but given it's not switching on, I'm sure there is no power. I'll check it tomorrow morning. Do you have a link for the wiring diagram on a 996? I'm happy to google it, but if you can share some direction it would be much appreciated!
I personally perfer hard copies and use the Bentley manual. Sorry u dont have an electronic copy but they r floating around.
Since u jumped the relay i would check continuity between the relay output (pin 87) and the conector at the compressor. Also make sure u have power at 30 (key on) if not then check the fuse and continuity. I think your issue is the power side not the trigger, although u need to check those wires to be sure.
D6 does feed the relay pin 87 on the heater relay, then it travels to pin 30 when that relay is active to the high pressure switch. If the hp switch is good it travels through to the ac relay pin 30
The heater realay should be #18 above the fuse panel and the ac relay is on the back shelf by the dme #4
Also, was the system empty if r134 when u changed the compressor? If so u will need to change the drier too. When u tried to charge the system did u pull a vacuum to remove the moisture? If u didnt the drier may now have to be changed.
Wow! You guys are the best. Found no 12v at the compressor, as expected. The melted fuse made me think something was wrong further down in the wiring. When I got to relay box 2 behind the rear seats, I found the issue. The wire between pin 87a on relay 4 going to slot 6 was completely toasted. Re-pinned the slots and added a new wire and viola! Compressor kicked on
Thank you tons! This was a life saver.
I did vacuum the system, we always do when doing A/C work.
Again, thank you guys for your help! On to finishing the top.
Nice work. It just sucks u spent the time and money changing the compressor and charging the system. I keep preaching diagnostics......it takes time but saves u money.
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