Ultimate LSX AC Control Tutorial - HalfSpec Engineering

[halfspec]

David

You're right. With the diagram I drew for Rob containing the erroneous 12V constant on the fan relay coils, I can see how you could get a path through each parallel fan relay coil, through D2, through the compressor relay coil, and through whatever other load on switched 12V that ties back to ground when 12V Switched is switched off. I've never seen an automotive relay contact latch with < 6VDC on it which is what you'd get in this situation because you'd get at least 3 voltage drops on that path + the 0.7v diode voltage drop drop, but even without latching, I believe you're right that a parasitic path would exist.

My apologies for doubting your understanding of the circuit 

For anyone else here reading, the takeaway it to always use 12V switched on the hotside of your fan relays if using my LSX AC Controller. By the time this post goes live, all the diagrams in this thread should be correct.

Lane

[Cobranut]

David

You're right. With the diagram I drew for Rob containing the erroneous 12V constant on the fan relay coils, I can see how you could get a path through each parallel fan relay coil, through D2, through the compressor relay coil, and through whatever other load on switched 12V that ties back to ground when 12V Switched is switched off. I've never seen an automotive relay contact latch with < 6VDC on it which is what you'd get in this situation because you'd get at least 3 voltage drops on that path + the 0.7v diode voltage drop drop, but even without latching, I believe you're right that a parasitic path would exist.

My apologies for doubting your understanding of the circuit 

For anyone else here reading, the takeaway it to always use 12V switched on the hotside of your fan relays if using my LSX AC Controller. By the time this post goes live, all the diagrams in this thread should be correct.

Lane

Thanks Lane,

Generally, it's always a good idea to use the same switched source for all relay COILS, that powers the device that triggers the relay.
If you're certain that the device floats all outputs when powered down, then this isn't necessary, but it's still a good practice.

[petawabit]

Anyone have any pointers on depinning the black/yellow wire that goes into the connector on the back of the driver side fusebox? I'm not seeing a tang where I poke from the front side and looking at the new male/female connectors on the new harness, can only see an indented square at the bottom of the terminal.  Tried gently shoving a flat head underneath that section and prying upwards, while pulling on the back from the wire with no luck.  thanks in advance!

[Ottocycle]

Hello everyone. I'm a new member here and signed on because of Lane's excellent tutorial. (Also his one on AC plumbing).
Thank you, thank you.

Let me say from the outset I am not an RX7 owner, but I am an LS swap enthusiast. I have a Volvo 960 wagon that I have completed a functioning 5.3 LS swap, without AC. I do not believe in re-inventing the wheel and have scanned the web to find solutions to issues I have encountered and wish to use Lane's excellent info for both my wiring and plumbing. I have learned a lot from this exercise and will learn a lot more before I'm done, thanks to people like Lane who choose to inform the rest of us.

I have a question regarding RPM limit switches. I have bought the other components for the wiring but am confused about the advertised ranges the RPM limit switches, since Baker's are no longer available. I checked on the Summit site and their switches run from a baseline of 1,000rpm, with no indication whether they can be adjusted lower to match specs. I contacted Intelletronix regarding their units adjustability but have had no response.

Does anyone know: (A) if the Summit switches can be adjusted to specs as they come from the vendor, or (B) can the input signal from the Chevy ECU fool the switch by intercepting it with a resistor or some other means.

Once again thank you for putting both tutorials together and if anyone has any insight into the questions please let me know.

[halfspec]

Hello everyone. I'm a new member here and signed on because of Lane's excellent tutorial. (Also his one on AC plumbing).
Thank you, thank you.

Let me say from the outset I am not an RX7 owner, but I am an LS swap enthusiast. I have a Volvo 960 wagon that I have completed a functioning 5.3 LS swap, without AC. I do not believe in re-inventing the wheel and have scanned the web to find solutions to issues I have encountered and wish to use Lane's excellent info for both my wiring and plumbing. I have learned a lot from this exercise and will learn a lot more before I'm done, thanks to people like Lane who choose to inform the rest of us.

I have a question regarding RPM limit switches. I have bought the other components for the wiring but am confused about the advertised ranges the RPM limit switches, since Baker's are no longer available. I checked on the Summit site and their switches run from a baseline of 1,000rpm, with no indication whether they can be adjusted lower to match specs. I contacted Intelletronix regarding their units adjustability but have had no response.

Does anyone know: (A) if the Summit switches can be adjusted to specs as they come from the vendor, or (B) can the input signal from the Chevy ECU fool the switch by intercepting it with a resistor or some other means.

Once again thank you for putting both tutorials together and if anyone has any insight into the questions please let me know.

Welcome! Wagons rule!

Intelletronix is a POS company and I too have written them and have gotten zero response. That said, I have used their switches in previous generations of my LSX AC controllers:




First picture = N3210 which is what I think you've been looking at. The second picture is of the S3012 which I don't think they make anymore.
I have more experience with the S3012 and know it can go down to 100rpm activation. It's probably been 6 years since I took the picture of the N3210 and I remember less about it, but the fact that it's pictured makes me think I got it going.
The Intelletronix datasheet doesn't mention anything about a lower limit of 1000rpm, so I'd say that like the S3012, you should be able to get down to 400rpm no problem.

http://docs.wixstatic.com/ugd/6a4159_ee484d64d1434d8091113711320ad93c.pdf

Oh, and resistor's won't help you fool / manipulate the rpm window switch activation / deactivation points. The only thing that could help you, is changing the settings from a 4 cylinder to a 6 or 8 cylinder. Remember, the LS tach sensor outputs 2 pulses / rev like a 4 cylinder. It's NOT like normal V8's that output 4 pulses / rev:
https://www.norotors.com/index.php?topic=23631.msg334117#msg334117

Lane

[Ottocycle]

Lane,

Thanks for the quick reply and info. I just ordered an RPM switch from Summit. (Its on backorder, perhaps by a few weeks). Hopefully I can make it work.
I will get going on the rest of the loom and get the plumbing sorted for now (as well as a warren of vacuum operated doors for the climate control system). I'm trying to make everything look as original and factory as I can.
Thanks again and I will keep you posted on my progress, assuming I don't need you to bale me out (no promises)!!!!!