I changed my efan over to a Volvo fan and used a thermoswitch to trigger the fan. My thermoswitch failed and I decided I wanted to see if it was possible to trigger my e-fan via the PCM. This offers two main benefits:
1 - you can have both "HIGH" and "LOW" speed (depends on your year of van)
2 - The PCM is probably the most reliable piece of equipment in the vehicle. No more depending on cheap chinesium sensors to trigger your eFan.
So about a year ago -- I worked with AstroWill and CopperFireMist to make this happen. Can't thank those guys enough -- no way this would happen without their input.
Difficulty-level: Medium
- The mechanical work involves removing the PCM connectors and adding 2 pins. If you've done it for your 4x4 swap, you'll already know how to do this.
- Obviously -- you'll need an e-fan for this too. You could use dual fans or a single two-speed fan (like me) and a way to trigger both speeds. You'll still need to use relays to control the modes -- but you can trigger those relays via the PCM. This walkthrough isn't mean to cover that -- you can see that in the numerous e-fan conversion threads.
- The tuning part involves finding someone willing to tune your van's PCM. AstroWill did this for me using a TunerCATS. Will he do it for you? I don't know. But we've done the hard work of figuring out which parameters to fiddle with -- so technically you could send your PCM out for a tune using our parameters.
Onward:
The Problem?
The problem is the V6 never came with electronic fans -- but the same 411 PCM is used for a lot of V8 equipped GM vehicles (Camaro/Corvette/etc.) that did use a two speed PCM-controlled fan (well it's actually a two-fan system, but that doesn't matter here). So technically, we guessed it was possible to "re-train" our V6 PCMs to trigger those wires just like the V8s do.
You can read the gensis of this build at the following thread:
https://www.astrosafari.com/viewtopic.p ... 0#p1350177
Here's how we did it -- CopperFireMist pulled a wiring diagram and for (01-05) you have the ability to add a two/speed and on 98-99 you can have a single speed trigger (not verified).
I'll cover the how-to for the 01-05 -- for reference, my van is a 04. I'm not sure which PCMs will play nicely with this -- but as with any tuning, there are lots of idiosyncracies, so your mileage may vary.
Step 1: Add wires to PCM connectors
You need to add a wires at:
Connector #1 (BLUE) - PIN42 for Low Speed Cooling Fan Relay Control
Connector #2 (GREEN) - PIN33 for High Speed Cooling Fan Relay Control
As you'll notice on the below wiring schematics, these pins trigger the fan on the Corvette (V8) and are empty on the Astro pinout:
When these are triggered, they will send 12V negative (ground) across that circuit. So after you add the circuits, connect the other ends of these wires to the relay/relays controlling your fan circuit to use as ground triggers. I used a Volvo relay -- so I connected PIN42 to the low speed ground trigger and PIN33 to high speed ground trigger.
NOTE:
- The easiest way to get the pins is to goto your local pick-n-pull and extract a few out of an existing connector -- keep about 3 feet of wire on the end of the terminal so you can easily solder into where you want them. This will also give you practice for when you take your actual PCM connector apart. Blazers are easy to access the PCM connectors, but if you want practice with an Astro -- do it on an Astro!! Here's how to do it:
- You can also buy the connectors if you want -- Part: Delphi 12084912.
Part #2 - Tune your PCM
This is probably dependent on what Tuner you use -- but AstroWill and I used Tuner CATS, because that is what AstroWill uses. You'll want to pull a "base tune" from your van and then edit that tune -- just to make sure you don't mess something up and to have a backup if you want to go back to where you started.
There are a few intracies:
1 - You need to turn "A/C Auto Recirculation" to "Disabled" -- no idea why or what these means, but without setting this parameter the Fan triggers will PWM as opposed to ON/OFF. Hat-tip to CopperFireMist for this one.
2 - You need to set "Fan 1 Delay Time" to "2 Seconds" or the fan will trigger on shortly when you turn off your ignition regardless of temperature (no idea why -- but this fixed that behavior)...
You can see the parameters in the table below:
I've attached a Dropbox link to the .cal file used in TunerCATS here. If you download a free trial of JET Tuner, you should be able to view this tune... but not flash your PCM with it.
https://www.dropbox.com/s/n6hvq5ho50iox ... 9.cal?dl=1
NOTE: I also changed my tire size in this tune -- so only use the fan-related stuff for this or your speedo will be off (I use 245/75/16).
Part #3 - A/C
Low-tech: I triggered my low speed fan to come on whenever the "AC Request" is active. You can get it at the back of the A/C Compressor or near the A/C switch inside the cab and can find details on what wire that is in the other e-fan threads.
High-Tech: I didn't do this -- but it seems you could get the PCM to trigger the fan based on A/C pressures, as the V8 systems do. It seems you could also get the fans to turn off at highway speeds, which would be cool too. Don't need fans for A/C when your going down the highway at 55MPH.
I outlined this to AstroWill in the following email:
Final Words
Was this worth it? I think so. Will you? Probably not. Using a 3rd party trigger is easier - but less robust. YMMV. I enjoyed the process for learning's sake and I'd do it again if I had access to a tuner. It looks OE/Factory - which I like.
Want to make it look even more factory? Add a maxi-fuse to your existing fuse panel to power your fan like this: https://www.astrosafari.com/viewtopic.p ... 2#p1559704
1 - you can have both "HIGH" and "LOW" speed (depends on your year of van)
2 - The PCM is probably the most reliable piece of equipment in the vehicle. No more depending on cheap chinesium sensors to trigger your eFan.
So about a year ago -- I worked with AstroWill and CopperFireMist to make this happen. Can't thank those guys enough -- no way this would happen without their input.
Difficulty-level: Medium
- The mechanical work involves removing the PCM connectors and adding 2 pins. If you've done it for your 4x4 swap, you'll already know how to do this.
- Obviously -- you'll need an e-fan for this too. You could use dual fans or a single two-speed fan (like me) and a way to trigger both speeds. You'll still need to use relays to control the modes -- but you can trigger those relays via the PCM. This walkthrough isn't mean to cover that -- you can see that in the numerous e-fan conversion threads.
- The tuning part involves finding someone willing to tune your van's PCM. AstroWill did this for me using a TunerCATS. Will he do it for you? I don't know. But we've done the hard work of figuring out which parameters to fiddle with -- so technically you could send your PCM out for a tune using our parameters.
Onward:
The Problem?
The problem is the V6 never came with electronic fans -- but the same 411 PCM is used for a lot of V8 equipped GM vehicles (Camaro/Corvette/etc.) that did use a two speed PCM-controlled fan (well it's actually a two-fan system, but that doesn't matter here). So technically, we guessed it was possible to "re-train" our V6 PCMs to trigger those wires just like the V8s do.
You can read the gensis of this build at the following thread:
https://www.astrosafari.com/viewtopic.p ... 0#p1350177
Here's how we did it -- CopperFireMist pulled a wiring diagram and for (01-05) you have the ability to add a two/speed and on 98-99 you can have a single speed trigger (not verified).
I'll cover the how-to for the 01-05 -- for reference, my van is a 04. I'm not sure which PCMs will play nicely with this -- but as with any tuning, there are lots of idiosyncracies, so your mileage may vary.
Step 1: Add wires to PCM connectors
You need to add a wires at:
Connector #1 (BLUE) - PIN42 for Low Speed Cooling Fan Relay Control
Connector #2 (GREEN) - PIN33 for High Speed Cooling Fan Relay Control
As you'll notice on the below wiring schematics, these pins trigger the fan on the Corvette (V8) and are empty on the Astro pinout:
When these are triggered, they will send 12V negative (ground) across that circuit. So after you add the circuits, connect the other ends of these wires to the relay/relays controlling your fan circuit to use as ground triggers. I used a Volvo relay -- so I connected PIN42 to the low speed ground trigger and PIN33 to high speed ground trigger.
NOTE:
- The easiest way to get the pins is to goto your local pick-n-pull and extract a few out of an existing connector -- keep about 3 feet of wire on the end of the terminal so you can easily solder into where you want them. This will also give you practice for when you take your actual PCM connector apart. Blazers are easy to access the PCM connectors, but if you want practice with an Astro -- do it on an Astro!! Here's how to do it:
- You can also buy the connectors if you want -- Part: Delphi 12084912.
Part #2 - Tune your PCM
This is probably dependent on what Tuner you use -- but AstroWill and I used Tuner CATS, because that is what AstroWill uses. You'll want to pull a "base tune" from your van and then edit that tune -- just to make sure you don't mess something up and to have a backup if you want to go back to where you started.
There are a few intracies:
1 - You need to turn "A/C Auto Recirculation" to "Disabled" -- no idea why or what these means, but without setting this parameter the Fan triggers will PWM as opposed to ON/OFF. Hat-tip to CopperFireMist for this one.
2 - You need to set "Fan 1 Delay Time" to "2 Seconds" or the fan will trigger on shortly when you turn off your ignition regardless of temperature (no idea why -- but this fixed that behavior)...
You can see the parameters in the table below:
I've attached a Dropbox link to the .cal file used in TunerCATS here. If you download a free trial of JET Tuner, you should be able to view this tune... but not flash your PCM with it.
https://www.dropbox.com/s/n6hvq5ho50iox ... 9.cal?dl=1
NOTE: I also changed my tire size in this tune -- so only use the fan-related stuff for this or your speedo will be off (I use 245/75/16).
Part #3 - A/C
Low-tech: I triggered my low speed fan to come on whenever the "AC Request" is active. You can get it at the back of the A/C Compressor or near the A/C switch inside the cab and can find details on what wire that is in the other e-fan threads.
High-Tech: I didn't do this -- but it seems you could get the PCM to trigger the fan based on A/C pressures, as the V8 systems do. It seems you could also get the fans to turn off at highway speeds, which would be cool too. Don't need fans for A/C when your going down the highway at 55MPH.
I outlined this to AstroWill in the following email:
You'd need some brazing skill to add a couple bungs -- and if I had the skills, I probably would have tried it.
Final Words
Was this worth it? I think so. Will you? Probably not. Using a 3rd party trigger is easier - but less robust. YMMV. I enjoyed the process for learning's sake and I'd do it again if I had access to a tuner. It looks OE/Factory - which I like.
Want to make it look even more factory? Add a maxi-fuse to your existing fuse panel to power your fan like this: https://www.astrosafari.com/viewtopic.p ... 2#p1559704