I have just installed my aluminum radiator and dual fans. With the wiring kit was a temp. sensor. I recently added Auto Meter gauges to my non gauge 69. Do I need to install this other sensor or can I run my fans off of the sensor that runs my gauge? Also if you have pics of your dual fan wiring setup could you post them also? I am bad at reading wiring schematics. Do I have to buy a seperate controller if I want the fans to kick on at a certain temp. and off at a given temp.?

you can't use your gauge sender for the fans. you need to install a sender for the fan relays; they can be wired together so they both come on at the same time with one sender. you don't need a controller to make the fans come on at a certain temp; just get the appropriate sender that is designed to word at the temp you want. the sender acts as an on/off switch for the fans while the gauge sender acts as an 'in between' switch that moves the needle of the gauage. here's a good schematic:
http://www.streetrodstuff.com/Products/Manuals/DualFanWiringDiagram.pdf

Where should this other sensor go? Presently I have one in the intake manifold.

Where should this other sensor go? Presently I have one in the intake manifold.


left or right head between cylinder 1 and 3 or 6 and 8.

Most heads have a plug between 2 if the cylinders, 1-3 & 6-8

I guess my only choice is between 1&3. I tried removing the plug earlier between 6&8 and broke off my extension in it. How did you guys route the wires from the heads? I am trying to keep things neat and clean, not hodge podge.

If you want both fans kicking on at 100% at a given temp then the seperate temp switch is the way to go, if you want independent control or variable speed you'll need a controller. Plus side to alot of the controllers is that they are programable and can work with your existing gauge sender.

If you want both fans kicking on at 100% at a given temp then the seperate temp switch is the way to go, if you want independent control or variable speed you'll need a controller. Plus side to alot of the controllers is that they are programable and can work with your existing gauge sender.

Tell me more. Brand of controller, cost and how to?

spal makes a fan-pwm controller. it was so bad i threw it in the trash and never looked back. the dummy relay system can't be beat.

spal makes a fan-pwm controller. it was so bad i threw it in the trash and never looked back. the dummy relay system can't be beat.

So John, from your experience you're suggesting using the second sensor and wiring setup?

as for calling it a 'second' sensor, i think of it more as the 'only' sensor for the fans. you won't see much of a difference that your gauge sensor sees compared to the fan sensor, but they are in different places. it' pretty simple, really: a single sensor gets into it's 'range', like 180 on, 200 off, or so, depending on what you want. it grounds out and completes the circuit that allows the two relays (one for each fan) to supply power to the fans, and then you have spinning fans. it takes a few wires and a place to put the relays, but works really well. i wired my 'temp' light into to the circuit to reassure me that my fans are coming on at the right time. it's been a year, and it's worked flawlessly. btw, if you want the idiot light to work, you'll need yet another sender for it!

spal makes a fan-pwm controller. it was so bad i threw it in the trash and never looked back. the dummy relay system can't be beat.
I've heard bad things about the SPAL unit as well. DC Controls, Dakota Digital, and Flex-a-lite all make pretty good controllers. Just depends on what you want, if both fans running full speed is what your after then the temp switch and relay setup is hard to beat.
I'm installing a two speed (single)Mark VIII fan and using the dakota digital controller along with two 75amp bosch relays.

I think what I want to do or be able to do is. Have the fans start at a certain temp. and off at a certain temp. while using my temp. sending unit that runs my temp. gauge. Which of the units mentioned best fit the bill for that?

I think what I want to do or be able to do is. Have the fans start at a certain temp. and off at a certain temp. while using my temp. sending unit that runs my temp. gauge. Which of the units mentioned best fit the bill for that?
That's pretty basic functionality, all three I mentioned can do that, I wouldn't use a controller ($80-$100) for what you can accomplish with a $15 temp switch(you can get water necks that have sensor ports if you need another location). If you want one fan to kick on a lower temp, then only kick the second fan on if the temp increases, then you're getting some value from the controller. You'll also need to upgrade the charge wire from your alternator to your battery especially if you set it up for both fans starting simultaneously, the surge current will be very high (well beyond stock wiring capacity).
The DC Controllers have PWM with the ability to slowly start the fans which can really help the surge issues.
I just upgraded my wiring and added a 6 gauge charge wire to the existing 10 gauge. This will allow me to add as many power sucking accessories as I please.

LCAC, do yu have any photos of your wiring set up? What's mounted where and wired to what? The existing wiring harness that I have is that of a 2 relay set up. It also came with a seperate sensor with a wire coming out the top. Which I would have to mount in my head. Also 2 connections aare marked + battery power. Should those be connected to the horn relay or just to the little junction block by the battery?

I also forgot to ask what you meant by temp switch? Like a sending unit?

I also forgot to ask what you meant by temp switch? Like a sending unit?
Yes, just like a sending unit except that instead of the resistance value changing with the heat it waits until it achieves a pre-set temp and closes an internal switch, then at another (lower) pre-set temp it opens the switch.

LCAC, do yu have any photos of your wiring set up? What's mounted where and wired to what? The existing wiring harness that I have is that of a 2 relay set up. It also came with a seperate sensor with a wire coming out the top. Which I would have to mount in my head. Also 2 connections aare marked + battery power. Should those be connected to the horn relay or just to the little junction block by the battery?
Not sure the pic's will help but here's mine in rough wiring.
A two relay setup would only be used to run the fans independently.Without seeing pic's or a diagram of the connections you mentioned there's no way to comment on where they should go. There will definately need to be battery power going to the relays but pulling from the horn relay will require some charge wire upgrades.

Forgot the link for the fan http://www.camaros.net/forums/showthread.php?t=126964&highlight=lincoln+mark+viii+install

Not sure the pic's will help but here's mine in rough wiring.
A two relay setup would only be used to run the fans independently.Without seeing pic's or a diagram of the connections you mentioned there's no way to comment on where they should go. There will definately need to be battery power going to the relays but pulling from the horn relay will require some charge wire upgrades.

In my kit I have the switch/sending unit. I think now this is the way for me to go so I won't buy a seperate controller. I'll just have to try and route my wires as neatly as possible. If I run battery power from the horn relay is a 10 ga. wire big enough? Or how about just connecting the battery power wires to the junction block by the battery? Does anyone have a pic of a non stock juntion block? The original seems a little small. I thought I saw in a post someone had one that kind of divided the wires apart.

Does anyone have a pic of a non stock juntion block? The original seems a little small. I thought I saw in a post someone had one that kind of divided the wires apart.
I pulled this out of a late model gm vehicle got a bunch of the fusible links from the harness as well, still grooming it but you get the idea, it's got a large 3/8" post to handle any current draw you may need.Here's a pic of my upgraded charge wiring through the horn relay (drivers side alternator)http://www.camaros.net/forums/attachment.php?attachmentid=5904&d=1205423562