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11-18-2017 | #1 |
Join Date: Jul 2017
Location: West Chester, PA
Posts: 378
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Electronic A.C. issues
Neither A.C. nor heat seems to work on my 90 ZR-1, wondering if it might be common failure mode? Electronic unit seems functional, but just blows cold air when it's cold out, hot air when it's hot out. Has anyone seen this on their s, or do you think they are separate issues?
Sent from my SM-N920V using ZR-1 Net Registry mobile app
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1990 Black/Black ZR-1 #1155 1993 White/Red coupe (Regrettably sold) |
11-19-2017 | #2 |
Join Date: May 2007
Location: Addison IL
Posts: 241
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Re: Electronic A.C. issues
The AC system is more complicated than the heating system. Fix the heating problem first.
Coolant always flows to the heater core when the engine running. There is no water valve for the heater core. Check the two large tubes running over the right wheel area. They should both be hot, close to the engine temperature. If not the heater core is clogged with debris. Try backflushing it. The 3/4" tube is the outlet. If both tubes are hot. Maybe the air temperature door has a problem. Remove the blower speed control module located on top of the HVAC air box. It has two electrical connectors on it. Observe the temperature door. Have a helper vary the interior temperature setting from 60 to 85 degrees. The door should move in proportion to the temperature request. If not there may be a problem with the servo motor. |
11-19-2017 | #3 |
Join Date: Jul 2017
Location: West Chester, PA
Posts: 378
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Re: Electronic A.C. issues
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1990 Black/Black ZR-1 #1155 1993 White/Red coupe (Regrettably sold) |
11-27-2017 | #4 |
Join Date: Dec 2005
Location: Delanson, NY
Posts: 913
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Re: Electronic A.C. issues
I hope you have more luck with your system than I did. Blend door motor (actuator) was bad. Have to remove most of the right side dashboard and the evaporator case to remove the heater core box then I was able to remove the actuator. I also have a 1990 no heat post. Here is a picture of the 1990 actuator on the heater core box.
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1968 convertible Lemans Blue, 1986 coupe Medium Blue NCRS Top Flight (sold), 1990 ZR1 #2529 Red NCRS Regional and National Top Flight (sold), 1990 ZR1 #2124 Charcoal Metallic NCRS Top Flight 2010 & 2018, 2003 Anniversary Red Convertible (sold) |
12-01-2017 | #5 | |
Join Date: Jul 2017
Location: West Chester, PA
Posts: 378
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Re: Electronic A.C. issues
Quote:
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12-01-2017 | #6 |
Join Date: Jan 2012
Location: Dallastown, PA
Posts: 189
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Re: Electronic A.C. issues
Although there's probably no correlation to your heat problem, you may want to try that which I do to my '90 once every year to 18 months to get the A/C working. Simply disconnect a battery cable for a moment or two and then reconnect it. I know something must be screwed up, but at least for me, the temporary cure is the quickest and cheapest. Good luck.
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12-02-2017 | #7 | |
Join Date: Jul 2017
Location: West Chester, PA
Posts: 378
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Re: Electronic A.C. issues
Quote:
Had to disconnect Battery recently for something else, so I imagine that by doing that I cleared any fault codes that were logged by the Elec AC computer. Who knows, maybe I'll get lucky! It'll give me something to do this weekend besides watching football. |
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12-03-2017 | #8 | |
Join Date: Oct 2017
Location: TX
Posts: 1,999
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Re: Electronic A.C. issues
Quote:
Found code 09 which corresponds to low freon. First step to repair is dis-connect the neagtive battery post for 15 seconds. ( Or there are a couple of fuses you can pull, but the battery is quicker). Upon starting the engine I noticed the light was not flashing and the AC worked. Upon further investigation I discovered the compressor cycling more than normal. Checked pressure and found it was at the lower limit. Added a touch of freon and checked for leaks. Found the high side schrader leaking just a tad. Tightened it and all is well. All that being said, you might see if your pressures are correct. If it is marginal your AC might set a code under certain conditions & by dis-connecting the battery you are removing the fault which allows the AC to function. Info on checking the codes, etc. is in the service manual. Worth a shot. Good luck. |
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12-02-2017 | #9 |
Join Date: Jul 2007
Location: Bartlett, IL
Posts: 7,154
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Re: Electronic A.C. issues
Also with electronic AC when you pull the battery. on first key, I always turn to on and waiting until after the blend door motor is done calibrating before starting the car
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1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978 |
12-03-2017 | #10 |
Join Date: Jul 2017
Location: West Chester, PA
Posts: 378
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Re: Electronic A.C. issues
Well, not sure what happened, but felt heat coming out of the vents for the first time yesterday on a short trip down to Effingham, IL. Pretty happy about that.
Since I was motivated by undeserved success, I took a look at my rear hatch support struts since I need to replace them and found that the passenger side electrical connector for the rear hatch defroster is gone, busted off by a previous owner. |
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