April 10, 2021, 05:07:06 PM

Author Topic: Ultimate LSX AC Control Tutorial - HalfSpec Engineering  (Read 72554 times)

Offline AZieger

Re: Ultimate LSX AC Control Tutorial - HalfSpec Engineering
« Reply #15 on: May 06, 2018, 02:52:14 PM »
So I realize this thread is kinda old, but I am working on implementing one of these kits into my LS3 swap and I have a question -

Why do you only have the low speed cooling fan activate within the RPM window?  From what I understand, the original RX-7 wiring would turn on the low speed cooling fan continuously as long as the A/C button was pressed (and the thermo switch was closed, and the blower fan was on of course).  Is there a particular reason why we want to turn the cooling fan off at 4800 RPM?  I thought most cars kept a cooling fan running for A/C regardless of RPM.
Z Precision

Offline halfspec

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Re: Ultimate LSX AC Control Tutorial - HalfSpec Engineering
« Reply #16 on: May 06, 2018, 04:37:41 PM »
It's a rough way of disabling the fans at speed since all the controller has access to is rpm feedback. The idea is that at a certain point the air rammed through the condenser at speed > the spal fans capacity. At such point the powered fan actually serves as extra resistance to the incoming air.

Without digging back into the fsm I'd say you're probably right about the fd not cutting the fans at speed, but its something you see a lot of in modern cars.

Hope that helps
Lane

Offline AZieger

Re: Ultimate LSX AC Control Tutorial - HalfSpec Engineering
« Reply #17 on: May 06, 2018, 04:47:46 PM »
Sweet, thanks for the fast response!  The logic is a little fuzzy, since RPM isn't really indicative of vehicle speed.  But you could look at it as another way to help get every last peak HP by reducing alternator load at high RPM!  Sounds like it would probably work fine either way - I just wanted to make sure I wasn't missing something.

Another oddity that I am trying to figure out is why the factory wiring in AT cars (like mine) bypasses the HVAC thermo switch for cooling fan control.  So in other words, the ground path for turning on the low speed engine cooling fans are:

MT: Thermo switch>A/C button>Blower Motor
AT: A/C button>Blower Motor

Any ideas?

Z Precision

Offline halfspec

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Re: Ultimate LSX AC Control Tutorial - HalfSpec Engineering
« Reply #18 on: May 06, 2018, 05:06:12 PM »
Agreed. Rpm is definitely not 1:1 with speed. It's just all I had to work with (without adding another black box) and my thinking was that after 4800 your either on your way to the redline or at least not  puttering around / city driving.

To my knowledge and my understanding of the fsm, stock AT AC control does not bypass the thermoswitch, nor is the thermo switch the first part of the signal. If you want to get technical its the blower switch - > ac switch - > thermo switch - > ECU and Relays. It's gone over in more detail in the 'how it works' section of this thread.

Actually its been a bit since I've looked at the aux AT pages of the fsm but from memory there's only one version of the climate control page in the fsm. Not two different ones for AT and MT. Likewise, I approached MTs and ATs identically when i used to build these kits for people years ago and never had issues.

If what you're describing is actually how yours is wired, it's not factory or its a year we didnt get in the US in which case all bets are off :P

Lane

Offline AZieger

Re: Ultimate LSX AC Control Tutorial - HalfSpec Engineering
« Reply #19 on: May 06, 2018, 05:16:36 PM »
You are correct, there is only one climate control page.  There is some "dashed" wiring shown on it though, and it matches the wiring in my USDM '93 auto.  The relay control wire that turns on my low speed fans is violet/purple, instead of violet like it is in the MT cars.  So it appears that AT cars bypass the thermo switch (see attached).

You are also correct in stating that it would not affect your customers if they follow your instructions.  I am doing it a little different, I am trying to re-use the fan control wire that is already in the harness (violet/purple in my case) just to keep things clean and prevent me from having to run more wires to my fan relays and/or open up the front harness along that whole length. 
Z Precision

Offline halfspec

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Re: Ultimate LSX AC Control Tutorial - HalfSpec Engineering
« Reply #20 on: May 06, 2018, 06:13:43 PM »
Oh yeah. The dashed wiring. I guess my rust is starting to show + the fact that I've been replying from my back porch with a drink in my hand and going from memory up to this point  :cheers:
I'll have to agree with you. It does look like a bypass in the FSM, but I would be very surprised if it actually is that way in a physical sense. The thermoswitch is integral to stopping the evaporator from icing up on any car. If I had to guess the lower dashed line is a FSM error and the it's actually just showing a pickup after X-07 as shown on the left path and it's just showing an AT specific offshoot to a ECU input on the auto ECU that gets feedback when the AC is on. It may be that the color of the wire going to the fan relay is V for MT or V/P for AT but I suspect both go through the thermoswitch. That's the only reason I can come up with in my slightly inebriated state. Otherwise, I don't think Mazda would have shipped AT FDs with thermoswitches (which they did) if they were simply bypassed.
FSM errors are not common, but I definitely wouldn't consider it infallible. I think I've personally found and confirmed 2-3 (retract relay comes to mind) errors myself. I'd say the only way to really get to the bottom of this 100% is to do some continuity testing.

Lane

Offline ls3_rob

Re: Ultimate LSX AC Control Tutorial - HalfSpec Engineering
« Reply #21 on: May 07, 2018, 05:30:21 PM »
Ok Lane here is a dilemma for you to help solve. My fan relay literally burnt up in my fuse box (30 side, 87 and 87a look like they got hot too). The wiring and fuse were fine  :scratch:

I am using the gmpp plug an play e67 harness kit for my ls3, samberg spal fans (2) and your ac ls3 wiring kit

I have used your ac wiring kit and it worked great for 2 years until it left me stranded overheating (no fan control).

I have the Samberg fans wired together using the single wire labeled fan from the fuse box and the other grounded to the chassis.

Am I pulling to much amperage for the 35amp provided in the gmpp fuse box?

I have put a 40amp relay in there with no problems since.

 :banghead:


07 tl type s daily
93 rx7 ls3

Offline Cobranut

Re: Ultimate LSX AC Control Tutorial - HalfSpec Engineering
« Reply #22 on: May 07, 2018, 09:10:48 PM »
Ok Lane here is a dilemma for you to help solve. My fan relay literally burnt up in my fuse box (30 side, 87 and 87a look like they got hot too). The wiring and fuse were fine  :scratch:

I am using the gmpp plug an play e67 harness kit for my ls3, samberg spal fans (2) and your ac ls3 wiring kit

I have used your ac wiring kit and it worked great for 2 years until it left me stranded overheating (no fan control).

I have the Samberg fans wired together using the single wire labeled fan from the fuse box and the other grounded to the chassis.

Am I pulling to much amperage for the 35amp provided in the gmpp fuse box?

I have put a 40amp relay in there with no problems since.

 :banghead:

Both those fans in parallel are way too much for one relay.

I used 3 40a Bosch-type relays for my fans, wired to allow two speed operation the way GM did originally.
There is a heavy gauge Blue wire in the front harness, that fed the original fan relays from a HD fuse in the front fuse box, that I used to feed the fan relays.

These, along with the other needed relays that replaced those in the front relay box, are mounted inside my Samberg radiator housing, on either side of the air filter.  Mount the tab facing up so water cannot accumulate in the relays.
1995 FD, 7.0 Liter stroked LS3, T56, 8.8, Samberg kit.

Offline halfspec

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Re: Ultimate LSX AC Control Tutorial - HalfSpec Engineering
« Reply #23 on: May 07, 2018, 09:28:16 PM »
Yeaaah. @Cobranut beat me to it. You're just dealing with a load that's > your wiring / fuse / relay capacity. Back when I used to build fan controllers I used 10AWG and a 25A fuse to run each fan. To do that with one wire / fuse / relay for a continuous 50Amp load you'd need 8 or 6AWG wiring, a 50A fuse, and a 50+ Amp rated relay. Seriously doubt your gmpp harness kit has 8AWG in in  :(

Now to be completely honest, my experience showed that the fans only really draw ~20amps at full speed. I just build in 25% overcapacity in my wiring / fusing because every fan is a little different and startup transients usually produce a spike that > 20amps.

Finally, just so everyone's on the same page. The AC controllers in this thread and the LS1 controller thread only provide coil control to the end user's fan relay of choice. The AC controller can turn on a 1amp rated relay. The fan controller can turn on a 80amp relay. It's up to the end user to choose the correct relay / wiring for his/her load. The AC controller simply turns the relay on/off. It can't burn up wiring and/or relays. :cheers:

Lane

Offline halfspec

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Re: Ultimate LSX AC Control Tutorial - HalfSpec Engineering
« Reply #24 on: May 15, 2018, 09:30:18 AM »
Something I whipped up for Rob via PM that I thought I'd share in case other people have similar questions about safely handling ~40amps of fan load:



It's just the LSX AC circuit in my first post with fan fusing, switching, and wiring added to show how 2 fans could be safely powered with a GM fan output + the AC controller fan output. This is catered to Rob's specification of one wire fan control so there's no low / high speed operation, but it is a nice way to do it since you have independent relays. I.E., if one relay melts, blows up and/or its fuse blows, the other fan should keep on trucking.

Lane

Offline Jakewah

Re: Ultimate LSX AC Control Tutorial - HalfSpec Engineering
« Reply #25 on: June 12, 2018, 09:19:56 AM »
Heads up to everyone, baker electronix is going out of business and it seems that the RPM Window Switch RWSR is no longer available for purchase:

http://www.bakerelectronix.com/products_rws/

Does anyone know of a drop in replacement?

Here are the specs Halfspec recommends in his parts list:

Reccomended Order Parameters = V8 LS1 Engine with a 2 pulse/rev Tach Signal
Enable RPM = 400 RPM (just under normal idle speeds) Disable RPM = 4800 RPM.


Offline Jakewah

Re: Ultimate LSX AC Control Tutorial - HalfSpec Engineering
« Reply #27 on: June 12, 2018, 10:54:47 AM »
Woohoo!! Thanks so much and thank you for somehow continuing to help our community out :)

Offline Negrok20r

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Re: Ultimate LSX AC Control Tutorial - HalfSpec Engineering
« Reply #28 on: July 30, 2018, 12:12:52 AM »
1.   Plug the 25A fuse into the 12V Switched wireís fuse holder which is near the relays in the passenger kick panel area.
2.   If your system isnít charged and your pressure switch isnít installed, youíll have to jump the pressure switch connector with something line a non-insulated (bare metal) paper clip. The pressure switch used with the LS2/LS3 kit is simply a on off switch and has no polarity. It stays closed when the pressure is right in the system and passes the signal through it. It opens up when the pressure is too low or too high and breaks the signal passing through it.
So, to test without actually having the system charged up and the pressure switch installed, you have to jump the two terminals on the pressure switch connector with something like a paper clip.
3.   Turn your key to the ON position (donít start the car yet).
4.   Check the RPM switch to see that its indicator LED turns solid blue then starts to pulse blue.
5.   Crank your car and verify that the RPM switchís main indicator LED turns slightly purple. This indicates that the switch is accepting the RPM signal from the PCM and adds some red light to the indicator LED which signals that the switch is allowing the AC to be turned on (IE the carís RPM is within a safe range). If you turn off the engine or rev over 4800 rpm you will see the the main LED turn back to solid blue (indicating that the RPMs are too low or too high for the AC compressor to be on).


RPM switch with purple indicator light (car on and idling)

6.    With the car still on, turn on your A/C blower motor, then press the A/C button. You should hear at least one of the relayís click or at least feel it click if you touch it while toggling the A/C switch. You can also check the compressor clutch connector with a voltmeter (if you happen to have one) and youíll see 12v. Additionally, if you have hooked up the fan control wires, you should hear and see your fans turn on. If it does youíre done with the exception that you may need to reconnect your compressor plug and pressure sensor plug if you unplugged them for testing.
If not, check the unitís 25A fuse. If the fuse is intact, check your ground terminal. If needed, clean the contact point again. If that fails, move the ground to another location. If it still doesnít click when pressing the A/C switch please post your questions here and the norotors member will help you.

Ok . After long 3 years I decided to install the ac, I did all the above and it worked great. But as soon as I changed the system and I turn on the ac the fuse on the lsx control blow.
I replaced the fuse and disconnected the compressor and  turn it on again and the fuse doesnít blow. But as soon as I connect the compressor again the fuse blow .
Then when the switch is accepting the rpm , when I rev the car the light indicator becomes solid blue at 2200 rpm instead of 4800 rpm? Antrying before 2200 rpm is purpleish.
I double check all my connection and directions in here and I did everything accordingly ..
Any one that had similar problems? Or have any idea as to what's going on?
« Last Edit: July 30, 2018, 12:29:02 AM by Negrok20r »
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Offline halfspec

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Re: Ultimate LSX AC Control Tutorial - HalfSpec Engineering
« Reply #29 on: July 30, 2018, 01:52:14 PM »
I'm pretty sure you've diagnosed a bad AC compressor clutch. I'd have to dig through my PM's but I'm pretty sure this happened to 2-3 people years ago when I used to sell the kits. When the clutches fail they hard short which blows your fuse.
If you wanted to be completely sure, you could hotwire in something small to the compressor plug like a turn signal or a car horn or something like that. The idea being that you could turn on the device as if it was the compressor and you would know that the AC controller is supporting a normal load correctly.

For the RPM window switch... What engine and gauge set are you running this on again? Normal LS engines have a tach output of 2 pulses / rpm and is what I had all the switches I ordered from baker electronix programmed for. So a 4800 rpm signal would be a 9600 PPS (pulse-per-second) signal. If you have a XYZ PCM that sends out 4 pulses / rpm (normal in most other V8 applications), your PCM would send out a 9600 PPS signal at ~ 2400RPM. If that's the case, the only way I know around that is to have the RPM window switch reprogrammed (http://www.bakerelectronix.com/) for a 4 pulses / rev application or buy a end-user programmable window switch. Unfortunately, Baker Electronix is closing from what I've heard :(

Lane