eRod Fan Harness

[davepl]

I'm setting up a GM eRod and am unhappy with the prospect of running my dual Spal fans as one big unit.

They only give you one fan control wire which is a bit odd. I'm hoping someone knows the pinouts and I can actually add a second relay in the fusebox, fix the calibration, and get back dual fan control. The calibration is set up for a single fan, but the calibration can still accept two if you change the values.

Failing that I could run both fans in series the whole time and then in parallel when commanded ON, but that's some relay magic and I'd rather not have them on all of the time, of course. Worst case I just run them as one big fan I guess but I'd really rather not.

Can anyone point me at a reference for pinouts and harness wire color or anything similar?

Many thanks,
Dave

[davepl]

From the E38 pinouts (but is that the same as the eRod???):

High Speed Fan - Pin 17, D-BU/WT
Low Speed Fan - Pin 58, D-GN

Are these switched ground? Would I be safe using them to ground a relay that I provide?

[Jon S.]

The Gen 4 engine E-Rod systems use an E67 ECM. The Gen 5 engine E-Rod systems use an E92 ECM.

Gen 4 GMPP wiring harnesses have the Low and High fan outputs merged. Follow the single fan output wire that you have, back to the area of the Fuse Block. You we will see where this occurs. You will find a Blue wire and a Green wire have been merged.

[davepl]

Thanks very much! I pulled it part and found the two wires (green and blue). Just to confirm:

a) Those are the two individual fan wires coming from the ECM?
b) I should be able to cut them and route them out to my own relays? Unless I can find terminals to build out the fusebox, which would be nice

I want to use the three-relay setup where they run in series (slowly) and then one on high and then two on high. I have the schematic for that somewhere.

My only concern is that the one wire is just dark blue, but every pinout I can find says D-BU/WT which I assume means a white stripe, but I'm not seeing it.

[Jon S.]

Thanks very much! I pulled it part and found the two wires (green and blue). Just to confirm:

a) Those are the two individual fan wires coming from the ECM?
b) I should be able to cut them and route them out to my own relays? Unless I can find terminals to build out the fusebox, which would be nice

I want to use the three-relay setup where they run in series (slowly) and then one on high and then two on high. I have the schematic for that somewhere.

My only concern is that the one wire is just dark blue, but every pinout I can find says D-BU/WT which I assume means a white stripe, but I'm not seeing it.

OK ... you should really get the correct schematics for your project. All GMPP instructions (E67) show a Green wire (Low Fan) and a Blue wire (High Fan) merging at "Fuse Bus Pos 7D". Most E67 cooling fan schematics use these same wire colors. Some E38 schematics show a Blue wire with a White stripe, for the High Fan.

Make certain you confirm these wires at the ECM connectors - don't just go by color.

[davepl]

The only pinouts and schematics I've found so far are for a Trailblazer, which uses a single fan. No luck finding a dual-fan pinout E67 schematic yet (not for lack of trying, but I might not be searching well).

I'll confirm at the connector before I assume anything, thanks.

Can you tell me what you mean by "All GMPP Instructions (E67)"? That sounds like something I should have, but don't. The eRod came with a 4-page sheet that doesn't have much information at all. I'd love to see what you're referring to, sounds like I'd be worlds ahead.

My doc doesn't contain the word "E67" nor does it show any wiring pre-relay!

I found a picture of the manual page, not complete, which shows:

Connector X1
Pin 58 Dark Green Low Speed Cooling Fan
Pin 17 Dark Blue High Speed Cooling Fan

[Jon S.]

I found a picture of the manual page, not complete, which shows:

Connector X1
Pin 58 Dark Green Low Speed Cooling Fan
Pin 17 Dark Blue High Speed Cooling Fan

What you have found is for an E38 ECM, not for the E67 ECM that would have came with your GMPP E-Rod kit. No offense, but it seems like you are in over your head. Perhaps resourcing some assistance with this project would be a good idea.

Anyway ...

Go to the Chevrolet Performance (formerly GMPP) website:

www.chevrolet.com/performance/parts-catalog.html

Download the appropriate Crate Engine Installation Guide.

Look at the ECM Connector Pinouts section. C1 (Blue) pin 54 is the High Fan output (blue wire). C3 (Gray) pin 49 is the Low Fan output (green wire).

Reliable schematics are not "found", they are purchased - from Alldata, or ACDelco, or Helm.

[davepl]

I was having trouble -finding- documentation, not understanding it. Pointing me at the GMPP catalog was condescending and not helpful by any measure. The word "pinout" does not appear in the PDF for the LS3, or I would have been done before I asked.

[davepl]

I found the info on LS1Tech.com, cut the wires, toned them out, found them at the expected cavities on the ECM connectors.

While I was waiting I built a three-relay circuit that will run the two fans in series (low speed) on Low Cooling and in parallel (full speed) when both High and Low are requested. Works great, but now all I need to know is whether they are switched ground or switched power.

I made a multi-column chart out of the info in case it's handy for someone else in the future.

[matty b]

All fan relay triggers are ground as is ALMOST every output on the PCM.

[Jon S.]

I was having trouble -finding- documentation, not understanding it. Pointing me at the GMPP catalog was condescending and not helpful by any measure. The word "pinout" does not appear in the PDF for the LS3, or I would have been done before I asked.

Not sure how this could be deemed to be condescending ... you can download (PDF) the Crate Engine installation instructions that I was referring to ... these show which E67 pins are used in the GMPP wiring harness.

Clearly you have no idea what you are doing.

[pannetron]

davepl's post was more useful -- looking at the crate engine PDF, it lists C1-54 and C3-49 as both connecting to "Fuse Bus Pos 7D" which doesn't clearly indicate (to me, at least) that they are fan controls. The wire out of that fuse block labeled "Fan" is downstream of the single fan relay in the fuse block. I'm hoping that when I open up the fuse box I'll see two wires that I can separate where they connect to one fan relay on its coil side. My installation already separate relays for my two fans.

[Jon S.]

davepl's post was more useful -- looking at the crate engine PDF, it lists C1-54 and C3-49 as both connecting to "Fuse Bus Pos 7D" which doesn't clearly indicate (to me, at least) that they are fan controls. The wire out of that fuse block labeled "Fan" is downstream of the single fan relay in the fuse block.

Without the GMPP PDF, you would not have known that the Fan outputs were merged, or without me initially posting this information. In addition to the GMPP PDF, you also need access to good schematics - this would have answered the "does the ECM power or ground the fan relay" question from earlier.

I'm hoping that when I open up the fuse box I'll see two wires that I can separate where they connect to one fan relay on its coil side. My installation already separate relays for my two fans.

Yes, you can separate the Fan output wires.

Getting the Fans to operate the way you want with a GMPP controller (E67) can sometimes be difficult. In the later GMPP calibrations the Fan(s) will run constantly once they are activated, unless the ECM sees a vehicle speed of 15 MPH or more.

[davepl]

I suppose just as there are faces made for Radio there are personalities made for the Internet.

But I digress. Pannetron, yes, when you open the fuse box (disconnect the input lugs, then it pops out with a fight) you'll find the green and blue are literally tied together and connected to the same relay trigger. I plan to simply split them and hook them up to some (Bosch style) relays.

If I could find all the terminals used by GM in the fusebox you could likely do a tidy job of wiring it up in situ, but I wanted a three-relay controller so have broken it out externally. Heck, there might even be room for that!

I will have a functioning VSS from the TKO, and will set my pulsewidth duty cycles to 100 or 0 until I have a better understanding of PWM and relays. But that's another thread.

[badazz81z28]

Is there an update to this? I had the fuse open and didn't even notice the two wires for the fans merged. I see there is a blue and a green wire, not 100% it's for the fans

[Alvin]

Check these out

http://www.pcmofnc.com/product/gmpp-...ric-fan-kit-3/
p-4966-gmppfan.jpg

[IARLLC]

That looks like a pretty sweet plug-n-play set-up. But I only see two relays. I guess if it is made to be a direct add-on for the GMPP set-up that makes sense. PCMofNC sells a three relay set-up (both fans on low or high) too though right?