Installing electric fan need help

[STROKED]

I bought the Derale fan controller part number 16749. They say its designed to run dual fans but comes with 30amp relay, i'm going to run dual fan (4thgen fbody) do i need to add another relay? or replace it with 70-75amp?



Is it ok to split the wire from my gauge temp sender (located on the intake manifold) to the fan controller?

I have 180 Thermostat what temperature do i set the fan to run?

[TnBlkC230WZ]

I bought the Derale fan controller part number 16749. They say its designed to run dual fans but comes with 30amp relay, i'm going to run dual fan (4thgen fbody) do i need to add another relay? or replace it with 70-75amp?

Is it ok to split the wire from my gauge temp sender (located on the intake manifold) to the fan controller?

I have 180 Thermostat what temperature do i set the fan to run?

I looked at it on Summit and it looks like a single controller with a 30/40 Amp relay. It also says for larger dual fans you will need two controllers. Without having the data sheet on that relay you don't know if it is rated at 40 amps max or 40 amps continous. I would personally change the relay to an Omron or DuraKool relay with a 40 amp continous rating (100+ amps surge) and call it good. These will run a Taurus fan on high. If you are running one 15 - 18 amp fan you will be fine with the one that is in there.

as far as temp, where do you want it to run?

[STROKED]

Well i'm going to run 4thgen Fbody dual fan which use's 3 relays that are 30amp from the factory 2 speed Fan operation. 1 relay controlls low speed, and for high speed 2 relays. So i'm guessing i would have to run the same setup? For my setup i just want 1 speed so that would be 2 relay's right? I would like to run both fan's using 1 controller if possible.

The bottom half of this schematic is what referring to. (Late production)
http://shbox.com/1/fan_schematic_1995.jpg

If i set the fan to go off lower than 180 degree's would the thermostat even open?

This is my fan setup

[BonzoHansen]

If the controller just trips the relay like fan switch, either use one bigger relay or run 2 regular ones, just split the trigger lead from the controller. I'd run 2 so if one fails I still have some cooling.

To do the 3 relay trick, you need 2 triggers/controllers, one at a lower temp and the other at a higher one.

[TnBlkC230WZ]

Well i'm going to run 4thgen Fbody dual fan which use's 3 relays that are 30amp from the factory 2 speed Fan operation. 1 relay controlls low speed, and for high speed 2 relays. So i'm guessing i would have to run the same setup? For my setup i just want 1 speed so that would be 2 relay's right? I would like to run both fan's using 1 controller if possible.

The bottom half of this schematic is what referring to. (Late production)
http://shbox.com/1/fan_schematic_1995.jpg

If i set the fan to go off lower than 180 degree's would the thermostat even open?

The schematic says the relays are in the under hood electrical center. Most GM electrical centers use Metri-Pack 280 relays which are limited to 35 amps because of the 2.8 MM pins. Get a single Durakool G85B series relay. It is rated at 60 amps continous and 120 amps inrush. It will run the high side.



Another thing about GMs wiring. Relay 3 only serves to wire the fans in series. It doesn't add any power. When the low speed is on, both fans are spinning. When relay's two and three are turned on, fan one gets its ground through relay 3 and both fans get full power. When low speed is on, the fans are wired in series and fan one gounds through fan 2.

The Dakota digital controller will control both fans with you eletrical temp gauge sending unit.

Also, I like that fan setup. What are the actual dimensions?

[STROKED]

I was hopping to avoid having to buy another controller i'm on a budget looks like the Dakota digital controller is pricey. The controller i have lets me remove the relay if i were to put a bigger relay that gets 60amps continuously and 120amp spike, would that work?

Here is the dimension, i'm using the Summitracing radiator and to fit them i pretty much just cut the edges of the fan shroud till i was able to line them up to the radiator. Here is the measurement i took from the fan after cutting it.

5.5 inch from fan shroud to the back of the fan motor
18 inch from the top to the bottom
27 inch across the whole unit

[TnBlkC230WZ]

Yes, that one relay shouls work. They are available from www.newark.com for about $6. You have to look closely at the one you select. They have surface mount, diodes, hoods and lots of options.

[STROKED]

Looks like a good website, but im having hard time understanding all those options. I tried to go threw there search option and was totally lost because of not knowing what those options on the relays are. Would you be able to suggest one or tell me which one to get.

SPDT or SPST-NO
80A or 100A

ill be plugging it into this harness (what fuse do you recommend. Has a 25amp fuse right now.)

[H2Ogbodies]

I pm'd you about some pics you need to check out from installs I've done. I use the Mark VIII fans and they fit that radiator dimension like a glove-I also have a really simple harness kit using a SPDT relay controlling two SPST 70-amp relays, two temp sensors and related wiring. Basically the two temp sensors (different ranges) serve to trigger the fans via the appropriate temp and you can add an over-ride or AC trigger by tying the ground circuit of the clutch coil in with the ground lead to the high speed relay. I have diagrams drawn up and it's super easy to install....with the temp switches and relays, you have two temperature ranges to work with....so either the low speed will be on or off but never at the same time for a dual speed fan and these harnesses will also work with dual fans though a single large fan is always more efficient than any dual fan setup. You don't want cheap relays and you don't want to use crappy parts store wiring. I build quite a few of these so if you need any help, let me know. I've tried every controller there is and while some work better than others, relay activations always work...and replacement parts are a breeze...which is something else to consider.

[85GPLEf41]

I pm'd you about some pics you need to check out from installs I've done. I use the Mark VIII fans and they fit that radiator dimension like a glove-I also have a really simple harness kit using a SPDT relay controlling two SPST 70-amp relays, two temp sensors and related wiring. Basically the two temp sensors (different ranges) serve to trigger the fans via the appropriate temp and you can add an over-ride or AC trigger by tying the ground circuit of the clutch coil in with the ground lead to the high speed relay. I have diagrams drawn up and it's super easy to install....with the temp switches and relays, you have two temperature ranges to work with....so either the low speed will be on or off but never at the same time for a dual speed fan and these harnesses will also work with dual fans though a single large fan is always more efficient than any dual fan setup. You don't want cheap relays and you don't want to use crappy parts store wiring. I build quite a few of these so if you need any help, let me know. I've tried every controller there is and while some work better than others, relay activations always work...and replacement parts are a breeze...which is something else to consider.

Would something like this work on the Intrepid Ramcharger fans? I have some most of the required parts such as relays, circuit breakers, wiring etc etc. What switches do you use for this set up? I tried the parts stores but they just wanted to sell me kits. I would like to try to wire something up on my own.

[TnBlkC230WZ]

Looks like a good website, but im having hard time understanding all those options. I tried to go threw there search option and was totally lost because of not knowing what those options on the relays are. Would you be able to suggest one or tell me which one to get.

SPDT or SPST-NO
80A or 100A

ill be plugging it into this harness (what fuse do you recommend. Has a 25amp fuse right now.)

Either will work. SPDT = single pole double throw. It will have five pins. SPST = Single pole single throw. It iwll have four pins. The SPST-NO = single pole single throw-normally open.

The NO position equates to off in most relays and the NC (normally closed) equates to the on position of the relay.

The SPDT relay will have a NO (Normally Open Pin) pin (87a) It is very rare that this pin is used. It will have power when the relay is off.

The dg85c/d relays use a 3/8 pin so they will not fit your controller.

This is the one I used. It has a diode so you have to correctly wire pins 85 and 86 for ground and power

http://www.newark.com/durakool/dg85b...lay/dp/30M9184

This one has a metal bracket, but no diode so you can wire pins 85 and 86 for ground or power. http://www.newark.com/durakool/dg85b...lay/dp/30M9184

[H2Ogbodies]

What year Intrepid fans do you have? 1997-older have bearing issues and that is the reason they were dumped at dirt prices. I know they fit the g-body radiators well but they have a weak motor design besides the bearing issue. 1998-up are better but still feature pancake motor design, not ideal imo. The three relay setup I use is for a single fan, dual speed such as the Mark VIII, Tuarus, T-Bird, etc. For dual fans like the LT1 or LS1, you would need 4 relays for low, high and tandem/AC/over-ride operation. I would need to draw up a quick diagram to be sure...I had one on my desktop but I can't find it-I need to go through my electrical folder and I'll post it up here...

[85GPLEf41]

What year Intrepid fans do you have? 1997-older have bearing issues and that is the reason they were dumped at dirt prices. I know they fit the g-body radiators well but they have a weak motor design besides the bearing issue. 1998-up are better but still feature pancake motor design, not ideal imo. The three relay setup I use is for a single fan, dual speed such as the Mark VIII, Tuarus, T-Bird, etc. For dual fans like the LT1 or LS1, you would need 4 relays for low, high and tandem/AC/over-ride operation. I would need to draw up a quick diagram to be sure...I had one on my desktop but I can't find it-I need to go through my electrical folder and I'll post it up here...

My fans are from a 98 intrepid. I am still trying to come up with a decent diagram including relays, temp switches etc etc

[86Cutlass383SR]

For dual fans like the LT1 or LS1, you would need 4 relays for low, high and tandem/AC/over-ride operation. I would need to draw up a quick diagram to be sure...I had one on my desktop but I can't find it-I need to go through my electrical folder and I'll post it up here...

Please do. I'm running the 88-89 f-body dual fans and I can't find a good schematic to wire mine up. Are these f-body dual fans single speed or 2 speed? I've had them wire up but wasn't real happy with how I had mine. I am using a Howell TPI harness but it doesn't incorporate the electric fans the way the factory does. A write-up on ThirdGen.org says to disconnect control from the ecm for better control anyway. I used a seperate Howell dual fan harness but wasn't really satisfied with it. It was basically one fan hooked to the head temp sensor and another wired into the a/c. Basically two seperate fan systems in one. I'd like them to work together like they're supposed to. Primary fan comes on and then the secondary comes on for additional cooling if needed. Then when you turn on the a/c it turns the fan(s) on. I'd like not to have to remember to turn them off/on.

[MonzaRacer]

I use the Oval GM relays those are some of the toughest I have ever used.
I have the part numbers in my other phone Ill post up the connectors and relays later, but I used to get them from junkyard with plugs for 10 buck a handful, which usually was 6 or 8.

[H2Ogbodies]

Ideally, I run two temp sensors so that the low temp one acts as the primary and is ground-relay controlled while the second temp sensor also is ground-relay activated but is also tied into the AC system. You can easily integrate an over-ride control in parallel.

[85GPLEf41]

I went to some auto part stores and they just kept trying to sell me the kits. What type of senders do you recommend? The ones i have seen online either have 1 or 2 terminals.The with a single terminal are ground activated right? Would you happen to have any part numbers? I hooked up my fans to 12volts and they are dual speed. Since i don't have a/c right now i was thinking both a high and low with maybe a manual override. Thanks

[H2Ogbodies]

I'll check for ya-youneed single spade temp switches, not sensors which complete a path to ground at a specific temp range. If you are running a computer, it doesn't matter what you "want" to run since the ECM needs to see the correct range for operation in closed loop. If this is a carb setup then it doesn't matter. Typically, I run the low range around 190 on/175 off and a high of 215 on/200 off. For various differneces in cooling system efficiencies, you need to allow for a span of +/-10 degrees between the two temp switch values. Plus, to avoid running the fans at freeway speeds, I would suggest plumbing both temp switches in the lower water pump inlet-this way, the coolant temp is maintained by the actual temp coming into the motor-who cares what the temp is leaving as long as the inlet temp is where you want it. This way, at higher sustained speeds, the air rushing through the radiator will keep the temps low enough that the fans will rarely come on. This is how you avoid having the fans coming on when you don't want them to. I'll look up the temp switches I use and post them here.

[TnBlkC230WZ]

I care what temp the water is coming out. The water coming in doesn't warp your heads, the hot water coming out does. The water coming in doesn't maintain your oil temps, the water coming out does. I don't care how cold the water coming in is. If the water coming out is too hot, then the water coming in is still not cold enough.

[H2Ogbodies]

Well...let's think about this for a minute...assuming you have no mechanical problems with your cooling system, you should see an average of 30 degrees or so between the incoming coolant and how much heat the engine builds up during normal combustion. Now, your temp. gauge will tell you what temperature your coolant is at, usually in the intake area, and that is regulated by the thermostat. IF your engine requires additional cooling @ idle or at part throttle cruising (ie city driving) then the incoming low temp sensor will see an increase in temperature and depending on the efficiency of your radiator, you will have a hotter coolant temp on the outlet but it won't be enough to even worry about. The slight increase in coolant temps prior to the fan coming on with low speed is insignificant-we're talking 10-15 degrees, and a slightly warmer engine is better than a slightly cool one-emissions output and thermal efficientcy prove that. It is imo pointless when using relays to trigger electric fans, that you place the sensor switch ground location ahead of the radiator instead of after it-downstream if you will. By placing the temp switch closer to the engine inlet you get a more accurate reading and better relay/fan control. And by using a slightly higher volume water pump, coolant bypass, etc. you can move the coolant out of the engine much more quickly anyway. This idea is two sides of the same coin if you will but I do it with relay triggered fans in mind.