Air Conditioning (AC) Removal
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- Second Gear
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Air Conditioning (AC) Removal
I was astounded that I could hardly find anything on AC removal after searching for a whole hour.
I've just removed 29 pounds of AC system from my engine bay since it's R-12 and I don't care to convert. A little extra fuel economy and performance is nice too.
I've removed all the mechanical stuff under the hood, and haven't touched the evaporator core or anything else inside, or electrical.
I don't plan on touching the evaporator core (unless you think it's easy), but I wanted to know what else I can remove. I'm particularly interested in what fuses and relays I can remove without interrupting anything else (I don't want to, for example, accidentally disable the radiator fans altogether). Will removing the two AC fuses and four AC relays in the engine compartment fuse box has any adverse effects?
I've just removed 29 pounds of AC system from my engine bay since it's R-12 and I don't care to convert. A little extra fuel economy and performance is nice too.
I've removed all the mechanical stuff under the hood, and haven't touched the evaporator core or anything else inside, or electrical.
I don't plan on touching the evaporator core (unless you think it's easy), but I wanted to know what else I can remove. I'm particularly interested in what fuses and relays I can remove without interrupting anything else (I don't want to, for example, accidentally disable the radiator fans altogether). Will removing the two AC fuses and four AC relays in the engine compartment fuse box has any adverse effects?
Last edited by Soul Shinobi on Mon Oct 20, 2008 6:07 pm, edited 1 time in total.
-Nick
1992 BC Legacy L Sedan AWD 5MT 272,000 - Wish you the best
1998 BK Legacy L Wagon 5MT 234,000 miles - RIP
2002 SF Forester S Wagon 5MT 215,000 miles - Current winter sleigh
1986 FC Mazda RX-7 GXL Coupe 5MT 155,000 miles - Summer cruiser
1992 BC Legacy L Sedan AWD 5MT 272,000 - Wish you the best
1998 BK Legacy L Wagon 5MT 234,000 miles - RIP
2002 SF Forester S Wagon 5MT 215,000 miles - Current winter sleigh
1986 FC Mazda RX-7 GXL Coupe 5MT 155,000 miles - Summer cruiser
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- quasi-mod-o
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I'm not trying to be a jerk, but anyone can take stuff out. So there really isn't much of a writeup necessary.
Did you remove the condenser? Drier? All the lines?
Did you remove the condenser? Drier? All the lines?
2000 Subaru Legacy B4 RSK
"Der Wahnsinn ist nur eine schmale Brücke/die Ufer sind Vernunft und Trieb"
*Formerly DerFahrer*
@entirelyturbo on social media, including Facebook, Instagram, Twitter, and TikTok
"Der Wahnsinn ist nur eine schmale Brücke/die Ufer sind Vernunft und Trieb"
*Formerly DerFahrer*
@entirelyturbo on social media, including Facebook, Instagram, Twitter, and TikTok
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Yeah, most of it was easy, and I only broke one bolt on my rusty 267,xxx mile car, but I had no idea how to take the condenser out. I did figure it out, eventually (remove grill, two bolts, removed driver's side line, pull up, remove passenger side line, pull out). Thankfully it can be done without removing the radiator.
Everything up to the evaporator (both sides of the system) is out, but how easy is the evaporator core? And can I remove the 4 relays and 2 fuses so there's no power rerouting when I put the defroster on?
Everything up to the evaporator (both sides of the system) is out, but how easy is the evaporator core? And can I remove the 4 relays and 2 fuses so there's no power rerouting when I put the defroster on?
-Nick
1992 BC Legacy L Sedan AWD 5MT 272,000 - Wish you the best
1998 BK Legacy L Wagon 5MT 234,000 miles - RIP
2002 SF Forester S Wagon 5MT 215,000 miles - Current winter sleigh
1986 FC Mazda RX-7 GXL Coupe 5MT 155,000 miles - Summer cruiser
1992 BC Legacy L Sedan AWD 5MT 272,000 - Wish you the best
1998 BK Legacy L Wagon 5MT 234,000 miles - RIP
2002 SF Forester S Wagon 5MT 215,000 miles - Current winter sleigh
1986 FC Mazda RX-7 GXL Coupe 5MT 155,000 miles - Summer cruiser
The evap core can be removed pretty easily. There's one or two bolts holding the evap core box in. The core can then be remoeved, and the box cleaned. The only thing you need to do is seal the holes on the box so air doesn't escape, and you need to cover the holes in the fire wall. There's really no harm in leaving the evap core in. If it were me, I'd probably remove the core and clean the box as it gets very nasty over the years.
I'd have to look at a wiring diagram for the AC relays/fuses. You need to leave the sub fan relays alone. I'm not sure if there is an A/C fuse per-say.
I'd have to look at a wiring diagram for the AC relays/fuses. You need to leave the sub fan relays alone. I'm not sure if there is an A/C fuse per-say.
Josh
surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT
If you need to get a hold of me please email me rather then pm
surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT
If you need to get a hold of me please email me rather then pm
i'm interested too, pulled all mine out up to the firewall, nothing inside yet though
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Alright, I broke out the wiring diagrams here.
...
And 45 minutes later, it seems that ... Hold on. Okay, another half hour later... Jesus Christ this shit's complicated. I mean, I can read a wiring diagram, but this is tough. We've got 4 relays, two of which seem directly related to the fans but the relays and two fuses are so intermingled it's anyone's guess. Everything is cross linked a lot. There's also a main fan relay that I can't find on any diagrams.
I guess I'll have to setup something to trick out the temperature sensor to force the fans on for engine temp and see if the fans go on with difference combinations of relays and fuses in place.
15 minutes more of looking at this and I've got a bit of an idea of how this works. It seems the fuses be necessary for the sub fan, and maybe the main fan. It's confusing because the fans are three wire/dual speed.
I guess I'm going to have to just plug and play with the coolant temp sensor. Looking at these specifications, the temp sensor's resistance goes down as temperature increases so I should just be about to bridge it.
I'll have to do it tomorrow, I've got homework now.
...
And 45 minutes later, it seems that ... Hold on. Okay, another half hour later... Jesus Christ this shit's complicated. I mean, I can read a wiring diagram, but this is tough. We've got 4 relays, two of which seem directly related to the fans but the relays and two fuses are so intermingled it's anyone's guess. Everything is cross linked a lot. There's also a main fan relay that I can't find on any diagrams.
I guess I'll have to setup something to trick out the temperature sensor to force the fans on for engine temp and see if the fans go on with difference combinations of relays and fuses in place.
15 minutes more of looking at this and I've got a bit of an idea of how this works. It seems the fuses be necessary for the sub fan, and maybe the main fan. It's confusing because the fans are three wire/dual speed.
I guess I'm going to have to just plug and play with the coolant temp sensor. Looking at these specifications, the temp sensor's resistance goes down as temperature increases so I should just be about to bridge it.
I'll have to do it tomorrow, I've got homework now.
-Nick
1992 BC Legacy L Sedan AWD 5MT 272,000 - Wish you the best
1998 BK Legacy L Wagon 5MT 234,000 miles - RIP
2002 SF Forester S Wagon 5MT 215,000 miles - Current winter sleigh
1986 FC Mazda RX-7 GXL Coupe 5MT 155,000 miles - Summer cruiser
1992 BC Legacy L Sedan AWD 5MT 272,000 - Wish you the best
1998 BK Legacy L Wagon 5MT 234,000 miles - RIP
2002 SF Forester S Wagon 5MT 215,000 miles - Current winter sleigh
1986 FC Mazda RX-7 GXL Coupe 5MT 155,000 miles - Summer cruiser
Honestly, I'd highly recommend you DO NOT mess with the AC fuses & relays. They're not hurting anything, and you're not going to lose any substantial amount of weight from it. Plus, jeapordizing the fans not working properly really isn't something you want to do.
I went through the diagrams a little while back in trying to figure out the control logic, and it is far from easy to decipher. There's a lot of manual logic used instead of how it would be done today inside of an ECU.
I went through the diagrams a little while back in trying to figure out the control logic, and it is far from easy to decipher. There's a lot of manual logic used instead of how it would be done today inside of an ECU.
Josh
surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT
If you need to get a hold of me please email me rather then pm
surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT
If you need to get a hold of me please email me rather then pm
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Removing the fuses and relays will prevent power draw when the system is set to defog, defog/heat, etc. I like to prevent wasting power for the sake of fuel economy/alternator stress/battery stress.
I jumped the coolant temp sensor and it seems to work fine without any of the AC relays or fuses. The elusive Main Fan Relay must override everything else. Mission accomplished.
I jumped the coolant temp sensor and it seems to work fine without any of the AC relays or fuses. The elusive Main Fan Relay must override everything else. Mission accomplished.
Last edited by Soul Shinobi on Wed Oct 22, 2008 3:53 am, edited 1 time in total.
-Nick
1992 BC Legacy L Sedan AWD 5MT 272,000 - Wish you the best
1998 BK Legacy L Wagon 5MT 234,000 miles - RIP
2002 SF Forester S Wagon 5MT 215,000 miles - Current winter sleigh
1986 FC Mazda RX-7 GXL Coupe 5MT 155,000 miles - Summer cruiser
1992 BC Legacy L Sedan AWD 5MT 272,000 - Wish you the best
1998 BK Legacy L Wagon 5MT 234,000 miles - RIP
2002 SF Forester S Wagon 5MT 215,000 miles - Current winter sleigh
1986 FC Mazda RX-7 GXL Coupe 5MT 155,000 miles - Summer cruiser
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- Second Gear
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Good advice:Legacy777 wrote:The evap core can be removed pretty easily. There's one or two bolts holding the evap core box in. The core can then be remoeved, and the box cleaned. The only thing you need to do is seal the holes on the box so air doesn't escape, and you need to cover the holes in the fire wall. There's really no harm in leaving the evap core in. If it were me, I'd probably remove the core and clean the box as it gets very nasty over the years.
-Nick
1992 BC Legacy L Sedan AWD 5MT 272,000 - Wish you the best
1998 BK Legacy L Wagon 5MT 234,000 miles - RIP
2002 SF Forester S Wagon 5MT 215,000 miles - Current winter sleigh
1986 FC Mazda RX-7 GXL Coupe 5MT 155,000 miles - Summer cruiser
1992 BC Legacy L Sedan AWD 5MT 272,000 - Wish you the best
1998 BK Legacy L Wagon 5MT 234,000 miles - RIP
2002 SF Forester S Wagon 5MT 215,000 miles - Current winter sleigh
1986 FC Mazda RX-7 GXL Coupe 5MT 155,000 miles - Summer cruiser
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- Second Gear
- Posts: 496
- Joined: Fri Apr 14, 2006 8:49 pm
- Location: Nashua, NH, USA
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- Second Gear
- Posts: 496
- Joined: Fri Apr 14, 2006 8:49 pm
- Location: Nashua, NH, USA
Actually, I'm going to do a full proper conversion in my heating and AC class just this week! I'll be doing the labor, what little of it there is, and parts will total to around $60 since my school gets parts discounted for educational purposes.
-Nick
1992 BC Legacy L Sedan AWD 5MT 272,000 - Wish you the best
1998 BK Legacy L Wagon 5MT 234,000 miles - RIP
2002 SF Forester S Wagon 5MT 215,000 miles - Current winter sleigh
1986 FC Mazda RX-7 GXL Coupe 5MT 155,000 miles - Summer cruiser
1992 BC Legacy L Sedan AWD 5MT 272,000 - Wish you the best
1998 BK Legacy L Wagon 5MT 234,000 miles - RIP
2002 SF Forester S Wagon 5MT 215,000 miles - Current winter sleigh
1986 FC Mazda RX-7 GXL Coupe 5MT 155,000 miles - Summer cruiser
I pulled the 4 AC relays and the AC fuse on my Touring Wagon months ago. I've had no ill effects, radiator fans still worked fine the whole time. I didn't remove my AC though. Its just plain stupid to run the compressor while trying to deice/defog in the winter, all it does is prevent max heat and wastes gas. Gonna reinstall them in April, just in time to start keeping things cool (and battling humidity).
93 Touring Wagon (EJ20G 5spd Swap) -- Finally back and running strong as ever!
05 Outback 2.5XT 5spd -- Now the wife can have her SUV and get in on the turbo Legacy goodness at the same time.
05 Outback 2.5XT 5spd -- Now the wife can have her SUV and get in on the turbo Legacy goodness at the same time.
Actually the reason why the compressor runs during defrost is so the AC system doesn't dry out. There is oil in the AC system which helps keeps parts like the compressor lubricated and from rusting from trapped moister. If you don't let the compressor run some time during winter to help circulate the oil, it will die out earlier.James614 wrote:I pulled the 4 AC relays and the AC fuse on my Touring Wagon months ago. I've had no ill effects, radiator fans still worked fine the whole time. I didn't remove my AC though. Its just plain stupid to run the compressor while trying to deice/defog in the winter, all it does is prevent max heat and wastes gas. Gonna reinstall them in April, just in time to start keeping things cool (and battling humidity).
91 Subaru Legacy SS (Driving) 3"TBE, Vrg FCD, 440cc, HKS Safc, Vf10, ebay FMIC, Jecs
92 Toyota Corolla (fixing then selling)
06 ZZR600
92 Toyota Corolla (fixing then selling)
06 ZZR600
I'm pretty sure the reason it runs on defog is because when the window fogs from humidity, just blowing outside air on it does nothing or makes it worse, so the AC is used to dry the air so it can actually remove the condensation (warm, rainy days come to mind the most).
I've seen AC systems dry out and sieze from years of non-use, but never from 1 season.
That said, I've been waiting until my system dies before I yank it all out anyways!
I've seen AC systems dry out and sieze from years of non-use, but never from 1 season.
That said, I've been waiting until my system dies before I yank it all out anyways!
93 Touring Wagon (EJ20G 5spd Swap) -- Finally back and running strong as ever!
05 Outback 2.5XT 5spd -- Now the wife can have her SUV and get in on the turbo Legacy goodness at the same time.
05 Outback 2.5XT 5spd -- Now the wife can have her SUV and get in on the turbo Legacy goodness at the same time.