Question: Manual Fan Switch?

[WillC4]

Looking to put a manual fan switch on my '94. But i am a bit on the clueless side on what i need, where to get it, and what to do to install.
Does anyone here have one of these? Car has 2 fans and i would olike a switch with three options: 1)Off 2)Primary fan on 3)Both fans on.
Thanks for any input yall can provide.

 

[C5sarge]

C4 Corvette Fan Switch 1984-1995 Manual - Mid America Motorworks

 

[Rabbit]

Get your fans programmed to come on sooner.:confused

 

[Bronze85]

Auxillary fan relay is under the drivers side hood latch behind battery on my 85. Instructions show it on the shroud???

 

[vetteoz]

i would olike a switch with three options: 1)Off 2)Primary fan on 3)Both fans on.

You would need a double throw switch with main fan grounded to one terminal and both to the other terminal

 

[vetteboy86]

It's possible to get away with a smaller switch (Less current carrying capability) if the switch controls relays rather than the fans. Hookup to relays would be similar to the above post, in that the relay coil would connect to the switch.

 

[WillC4]

C4 Corvette Fan Switch 1984-1995 Manual - Mid America Motorworks

Thanks for that, decided to order that instead of getting more complicated with multi switch setups.

Get your fans programmed to come on sooner.

I would, but i dont want to spend x more dollars for a tune. Plus i would like to activate the fans at will vs automatically.

 

[G Winter]

The ECM turns on the fans by completing the grounds to the relays. To turn on both fans tap into those grounds with two wires. Connect to a double pole single throw switch,ground the other side of the switch. This keeps the relays isolated.

Glenn

 

[C5sarge]

Thanks for that, decided to order that instead of getting more complicated with multi switch setups.

Glad to have helped. When I had the 93 I installed this switch because of the heat here during the summer. Seemd to help a lot. I also used a product called "water wetter" in the cooling system which seemed to drop the temps another 5 degree's.

 

[WillC4]

Glad to have helped. When I had the 93 I installed this switch because of the heat here during the summer. Seemd to help a lot. I also used a product called "water wetter" in the cooling system which seemed to drop the temps another 5 degree's.

Yeah i have water wetter in the system right now, havent really knoticed temp differences, car usually maintains between 190° and 200° when moving unless that is it working its magic.

One more additional question, was reading the install instructions, and it doesnt seem to specificazlly clarify, but i splice into the signal wires? or remove signal wires and plug switch ones in?

 

[vetteoz]

One more additional question, was reading the install instructions, and it doesnt seem to specificazlly clarify, but i splice into the signal wires? or remove signal wires and plug switch ones in?

You splice in.
That way you have manual fan control when you want and the computer runs the fans as normal otherwise.
If you cut the control wires to the computer you have to remember to turn fans on every time

 

[C5sarge]

You splice in.
That way you have manual fan control when you want and the computer runs the fans as normal otherwise.
If you cut the control wires to the computer you have to remember to turn fans on every time

Correct. The kit comes with clip on splice connectors.

 

[Hib Halverson]

While manual fan switches might be peace of mind, very few drivers are attentive enough to monitor the coolant temperature as accurately and as often as can the ECM.

You'll be better to save the money and the labor and buy a handheld programmer which can change the "fan-on" temperatures in the ECM program. That will also do one thing the manual switch cannot and that is preserve the ECM's "staged" fan on strategy used on 90-up cars. With a reprogrammer, you keep that strategy but lower the temperatures at which the fan-ons occur.

Lastly, if you are considering a manual swtich because the car is "running hotter" than it has in the past, I'd diagnose the problem that's causing the higher ECT and find a solution rather than just turning on the fans in hopes that would be a fix.

Two common problems with C4s on which the ECT has "creeped up".

1) Front air dam faulty or not in place
2) Debris in front of the HVAC condenser and between the HVAC condenser and the radiator.

A third but less likely problem is a faulty cooling fan. Instructions for testing the fan system are in the FSM

 

[WillC4]

While manual fan switches might be peace of mind, very few drivers are attentive enough to monitor the coolant temperature as accurately and as often as can the ECM.

You'll be better to save the money and the labor and buy a handheld programmer which can change the "fan-on" temperatures in the ECM program. That will also do one thing the manual switch cannot and that is preserve the ECM's "staged" fan on strategy used on 90-up cars. With a reprogrammer, you keep that strategy but lower the temperatures at which the fan-ons occur.

Lastly, if you are considering a manual swtich because the car is "running hotter" than it has in the past, I'd diagnose the problem that's causing the higher ECT and find a solution rather than just turning on the fans in hopes that would be a fix.

Two common problems with C4s on which the ECT has "creeped up".

1) Front air dam faulty or not in place
2) Debris in front of the HVAC condenser and between the HVAC condenser and the radiator.

A third but less likely problem is a faulty cooling fan. Instructions for testing the fan system are in the FSM

I do appreciate this informative write-up.

Whenever i drive the '94 i pretty much have the digital coolant temp displayed all the time.

I dont consider the car as running hotter then in the past other then cruising temps are about 5° - 10°F higher after i tuned the car up (new water pump). However, at that time i was under the impression that i had a 180° T-stat, but apparently, previous owner put a 160° t-stat in, and i replaced it with a delco 180°. My fans (at least the primary fan) still activate at the stock 228°F as of two days ago.

I already ordered the switch, and will personally install it in the near future. I will eventually get a tune for my car, probably from pcmforless, and have the fans programmed to come on at around 200°F. But until then I would manually turn on the fans when engine temps reach around 200°F when traveling in traffic or sitting in the staging lanes at the track and turn off at about 185°F, that way i can make a routine for myself.

*On the side note, i deleted my A/C, and will be replacing my front air dam soon.

 

[Hib Halverson]

Ok. Now that you've given more info....for drag racing and cooling the engine in the lanes, I'd install that switch and wire it to run the fans constantly when needed but otherwise are controlled by the ECM. Also, you don't need a custom tune to change the fan-ons. A handheld programmer will do that and, in fact, if the engine is stock or near stock, you won't need a custom tune, anyway. On the other hand, if it's significantly modified, then you need to reprogram.

The front air dam will be very important to cooling at highway speeds. If you don't have it, the car will run hot.

I'd also verify the fan system is working properly.

 

[C5sarge]

Ok. Now that you've given more info....for drag racing and cooling the engine in the lanes, I'd install that switch and wire it to run the fans constantly when needed but otherwise are controlled by the ECM. Also, you don't need a custom tune to change the fan-ons. A handheld programmer will do that and, in fact, if the engine is stock or near stock, you won't need a custom tune, anyway. On the other hand, if it's significantly modified, then you need to reprogram.

The front air dam will be very important to cooling at highway speeds. If you don't have it, the car will run hot.

I'd also verify the fan system is working properly.

Nice info Hib. C4's tend to run on the hotter side anyway. Good luck Will.
Sounds like your on the right path.

 

[WillC4]

Nice info Hib. C4's tend to run on the hotter side anyway. Good luck Will.
Sounds like your on the right path.

Thanks, ill get yall some feedback when the switch is installed.