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Discussion Starter #1
I have the windstar set-up on my son's 70 chevelle. We have the fans hooked to individual bosch relays and a manual switch. The manual switch is temporary until I can figure out how to wire the mechanical temp sensor switch. I have been reading the posts concerning this and I am thoroughly confused.


This car does not have A/C. I would like the fans to come on at 195 and go off at 185. I would also like to be able to manually overide this system both ways, off and on. The temp sensor is an adjustable mechanical sensor from, JC Whitney, with a probe that attaches to the back of the radiator fins.

Can the connections be explained in this forum, or is it to technical to type out?

If you are familiar with the bosch relays;

1. ground wire of both fans are connected to a ground on the radiator core support.

2. the hot on the fans is connected individually to the #87 terminal on their perspective relays.

3. the #85 terminal, relay grounds, are connected to the radiator core support ground.

4. the #30 terminal on the relays are connected to the batt pos. terminal block on the firewall.

5. the manual switch is connected to a battery hot, (terminal block on the firewall),. The other side of the switch is connected to the #86 terminal for both relays.

This set-up works well with the one manual switch. I just don't know how to add the other options into the set-up.

thanks.............bk
 

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the temperatur sensor switch you got from JC whiteny will not turn on at one temperature and then wait to turn off at antoher temperature. This was a problem for my Mark VII fan. having it turn on and off about 800 times in one trip wasn't too much fun.

You have options for the temp control switch.. see the other post.

I think Chev-hell (the windstar guy
) has some shematic drawings on his website.

If you'd like I can draw you something on paper and fax it to you. I currently run the switch you want, It's : On / Temp sensor / Off

Be sure your Radiator support is grounded well to the frame and, in turn, to the battery negative terminal.

------------------
71' 3880# with me. Big Block 402, Merlin oval heads, 10.2:1CR, TH400, 3.73 posi,
1/8th: 8.0 @ 88mph
BEST 60': 1.85 w/street tires.
BEST 1/4: 12.5 with 1.89 sixty foot (street tires)
BEST MPH: 109mph

Picture of me roasting the tires and other guy stuff
Video of me staging (smoke of course)

[This message has been edited by BB_Mike (edited 03-06-2002).]
 

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This is the schematic I use. I hope you can modify it to fit your needs, you and I have slightly different equipment. I have 2 perma-cool fans (9.5A each), and a perma-cool adjustable fan controller (I highly recommend this!). This controller has the same kind of probe for sticking in the fins. I only use 1 relay. (a cheap one at that! no failure for 2 years...yet)

http://www.chevelles.com/showroom/FAN-WIRING.jpg

The DPDT switch is 3 positions. The middle one being OFF. I use the up position to mean ON and the down for AUTO (temp sensitive)The light bulb indicates if the fans are currently on, wether in the ON or AUTO position.

The perma-cool controller has a trigger wire intended to turn your fans on when you turn the AC on. I just used this wire to hook it into the switch to force the controller into turning the fans on when switch is in the ON position. The controller also has 2 outs for the fan power, but they are both switched on and off at the same time (not ever seperately).

With this setup note:
- with the 2A relay fuse always on, the relay is always on, unless you put switch in OFF pos. This means in AUTO, the fans can come on at any time if the rad gets hot enough. (and it does, after parking) Be careful! Maybe try hooking this up to ign. switched 12v instead. I wanted to be able to turn the fans on at the dragstrip and walk away for a few min without leaving the key in my car - I have no idea why, just thought I might want to.

It took me many hours of thinking to figure this out, I'm an ME not an EE! I'm sure someone else can help you figure out how to use your multiple relays in similar fashion as this. Perma-cool says that the controller is good for 20A, and I use it at 19A. It is specifically intended to switch fans, so I don't really think you NEED multiple high amp relays. I also think the reason I can get away with 1 cheap 30A relay is that it is pretty much always on - the controller does the actual switching. The relay really does little switching, unless I turn things OFF.

Wow, long winded good luck ask me if you have anyquestions see ya

chris
 

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Discussion Starter #4
I would love to have the drawing of your system. I am much better if I can see something, thanks. I have the battery in the trunk, grounded to the body of the car. In front I have a 1/0 cable from the body to the engine. Then from the front of the engine I have a #8 wire to the radiator support. I also have a normal ground strap from the firewall to the frame. This car is grounded good. Thanks for your help........bk

email is: [email protected]

[This message has been edited by driverk (edited 03-06-2002).]
 
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