PIN 33 for fan relay not constant ground? (Relay Clicking)

[MadRatt]

I have a CPW wiring harness with 2 fan relays and I have 2 Efans installed. In scanner I can activate (test) each fan. Fan 1 comes on no problem. Fan 2 the relay just clicks and no fan. I swapped relays thinking it might be a bad relay. Same result. So tested the input from the pin #33 and it is ground and is just clicking(not constant) why would this be putting out a -pulse? I understand that the relays are negative activated, but a pulse instead of constant? Fan 1 is constant when activated. Is there a solution in HPT that I can do to resolve it?

Any help would be appreciated.

[Mbrowning]

What ecu are you using?

[MadRatt]

P59 Ecu. I just went out to the shop and tried something. Test fans in scanner. Fan 2 comes on now if I also have the ac clutch on in system test. Turn off ac clutch and fan 2 relay just clicks! no fan. What is wrong here? I'm confused. Do I need to wire both fans to fan1 so they both come on at the same time. Then wire fan 2 to only come on with the ac? I shouldn't have to do it that way. I should be able to set up temp parameters for both with ac being the override as it shows in the system setting of HPT. Maybe I have something wrong.

[IARLLC]

Well P59 is GEN3 so:
This will help with your settings:
https://forum.hptuners.com/showthrea...ight=fan+patch

This is my preferred way to run 2 fans (3 relays):
https://forum.hptuners.com/showthrea...ol-help-please
post #8

Good luck with it!

[MadRatt]

Hey IARLLC,
Finally an answer. I searched for this on here and on LS1tech.com and couldn't find it. I will try this I hope its the answer i'm looking for.
Thanx for responding.

[IARLLC]

You are welcome.

My Tahoe has a P59 with this exact set-up. It works great. With the 3 relay set-up it runs both fans quietly for most cooling and AC needs, rarely needs the fans to go full speed even running the AC with a warmed over 6.0 in 120 degree weather. I have done it on several others as well. I am sure it will work out well for you.

[MadRatt]

Flashed the new fan patch over. It worked!! Fan #2 coming on when commanded in the scanner. Still just doing the 2 relay set up. So #1 comes on high then #2 when it gets hotter or when AC is on. Now I just have to get some ac lines made and charge it up and I should be good on this front.

Thanx again for your help IARLLC
Now if I we can just figure out my other issue in that other post I'll be set. LOL

[mbray01]

Be careful running 2 relays and only 1 fan coming on first then second for high. You may get a re-circulation happen if the fans are shrouded and actually create a running hot condition. This is the purpose of the 3 relay setup, to stop that

[IARLLC]

Yep. What mbray01 said.

If the two fans are together in the shroud (not separated by any kind of wall between them) the first fan will just pull air through the other fan hole....not much through the radiator.

[MadRatt]

Im using a new 2000 intrepid dual fan. Had to set them up as pushers. Seems to be working. #1 Fan comes on at 205 and drops it to 201 at idle. When I went on the short test drive never got above 201 to trigger it.