04 truck Efan problem using pins 33 and 42

[BlackGMC]

Actually, if pin 33 is good, that should be all I need. Thanks.

That is what I am trying to tell you Pin 33 on 99-02 is not the same asn 03+. I believe it is used for something completely different. At least this is what I have been told.

[kbbrett]

It looks to me like C1 42 is not used on an '02 truck. C2 33 is blend door.

[ChipsByAl]

Kbbrett you are correct. The Blue connector C1 terminal 42 is not used on the 2002 truck. On the Red connector C2 terminal 33, that circuit is used to control the recirculation door for the A/C. If you have the automatic climate control, this circuit is not used directly by the PCM. For vehicles with manual A/C controls the PCM will force recirculation mode if the high pressure gets out of range. The user control of the recirculation door will still be functional. In either case the switch at "G0106" needs to be changed to fan #2 control to allow PCM control of both fans.
The primary fan control is at C1-42 and secondary fan control is at C2-33. If using only one fan, use the primary circuit.
Al

[Chevy366]

Part of the problem people will buy a Nelson Harness which is not made for the 05 34" fans (LS1 27") and try to use it , he needs to add a another trigger wire and re-configure the relays .
And another bad thing is most people will do a harness for the larger fans (05 34") and not add any protection (fuses 40 amp min) , oh well .




Bottom view


Factory harness and will work for most trucks .
Went up a few dollars now close to 2 , part #15216042 .
See the fuses and large relays , what you need for the larger fans .

[ChipsByAl]

I would recommend the three relay setup if you are planning on using dual fans. For low speed, both fans run at low speed in series. On high speed, both fans run with full voltage in parallel.
AL

[Chevy366]

Factory Diagram :
Yours is close .

[99Silver6.0]

I built my own harness. Made an EXACT copy of the GM harness. Im not paying $200+ for a harness I need that comes with a harness I dont. Im into my harness a whole $40 bucks and some time. And it works the same way as the GM unit.

[Chevy366]

I built my own harness. Made an EXACT copy of the GM harness. Im not paying $200+ for a harness I need that comes with a harness I dont. Im into my harness a whole $40 bucks and some time. And it works the same way as the GM unit.

$40.00 not bad , I got the factory harness when they were 108 to the door .
They must have caught on to what people were doing and raised the price .

Can you give a link to the relays and fuses you used ?

[99Silver6.0]

Id link ya to the relays but I got them local. I didnt skimp it ont he relays. I got 3 70amp Cole Hersee SPDT relays at $8 a pop.

Sockets same deal, got them local. They look kinda like these though. http://www.partsexpress.com/pe/showd...number=330-075

Fuse block isnt sealed but I chose it for the heavy wiring it had. Has HUGE power wires on it. $15


But all in all worked well. I hid all of it right under the main fuse panel. Had to remove the big plastic cover that snaps off. Ill get some pics tomorrow.

On a side note, you will need 2 PCM pins!!

[Chevy366]

Id link ya to the relays but I got them local. I didnt skimp it ont he relays. I got 3 70amp Cole Hersee SPDT relays at $8 a pop.

Sockets same deal, got them local. They look kinda like these though. http://www.partsexpress.com/pe/showd...number=330-075

Fuse block isnt sealed but I chose it for the heavy wiring it had. Has HUGE power wires on it. $15


But all in all worked well. I hid all of it right under the main fuse panel. Had to remove the big plastic cover that snaps off. Ill get some pics tomorrow.

On a side note, you will need 2 PCM pins!!

Wow 70 amp Single Pole Double Throw (SPDT) relays , should last .
The fuse block , where did you get that at ?
Pics would be nice .
When I made one I used these : http://www.alliedelec.com/Search/Pro...CCCE003BA7E17F
They worked real nice because you can link them together .
PCM pins , someone else has posted this link but here it is again http://www.eficonnection.com/eficonnection/100w.aspx

Thanks for the info .