Hello,

I have searched the forum and found a lot of useful information on this subject but even after searching and reviewing the owners and repair manuals I still have two questions and hope someone can help me out.

I am installing a new CFS in my 94 coupe. It's located on the passengers side of the engine cylinder wall. The installation instructions call for me to tap the wires from the new CFS to the signal wires of each fan at the connectors located ont the other side of the engine conmpartment. This seems like a long routing and I was wondering if anyone has done this same job and has any routing advice. Also I can't seem to find any definite pictures or information showing the wire assignments at the connectors allowing me to identify which is each fans signal wire. Can you tell me how to indentify the correct wire at each switch.

 

Fan 1 Hot Light Blue.. Fan 2 Hot Black
Fuse block Fan 1 & 2 Hot Red
Primary & secondary relay Pink
Or I can scan a copy of my manual to your email

 

I take it the primary fan is fan 1 and the secondary fan is fan 2?

 

If all you are doing is replacing the switch then there should already be a wire to plug the new switch into.

 

What is CFS? Why does everyone think we are all clairvoyant and know exactly what the abbreviations people post means? If it is coolant fan switch, there isn't a cooling fan switch on your 94. The cooling fans are turned on and off via a relay. If you are adding a manual switch to turn on your fans at will, how would you expect us to know what was supplied in the kit?

 

As jfb notes he doesn't have one.
Only 84/ 85 have a fan switch ( as well as 86 - 89 equipped with Aux fan option).
All other years fan(s) control is by ECM only

The "new "one he quotes is new to the car; not a new stock replacement.Bad choice of words

That is why we own FSM's ( another abbreviation) for our cars

 

First let me say that I always appreciate any help I receive from the forum.

Now I live in Arizona where we really know what heat is and the C4 is a pain when it comes to over heating. I have included a picture of the kit I am trying to install and a relevant page from the documentation that refers to the terms I used.

Image of Kit:

Image of Documentation:


Last of all I would usually not reply to this but I feel a little perspective when it comes to ROD J & JFB. As senior members I am surprised and your replies. JFB you probable get a lot of bone head question but you need to take a nap before you reply in the afternoon. I am sorry if you had a bad day but I was not the reason. RODJ I happen to be one of those rare Americans who paid his own credit cards off in full and has a current mortgage with equity in his home. My wife and I work and it has been anything but easy to put myself, two kids through college and have a third getting ready to graduate on our dime. I have a service manual but could not afford the $140 for the official Field Service Manual sorry but my kids and family had bills to cover. I need help not criticism so if you both can assist I thank you.

 

On my 87 my aftermarket CFS is installed on the drivers side. Less wiring that way.

All you have to do is find the terminal on the fan relay(s) that the ecm grounds to turn the fan on and connect there. This will be the dark green /white wire.

I only have manuals up to the 91 model so haven't got a diagram to post.

 

http://www.chevythunder.com/1994_lt1_ecm_pg_6.htm

 

There isn't a fan switch installed in the head of a '94 - both fan relays are driven (grounded) by the PCM based on input from the Coolant Temp Sensor or the A/C Pressure Switch. You will need to remove a pipe plug from either head to install the switch then splice into the ground side of the Fan Relays. Do not disable the a/c side or it will blow up.

 

Thanks for all the replies and Rodj thanks for the wiring diagram. I am looking for the pipe plug Sun Cr is referring to. They call it a jacket plug in my instructions and from my research it is supposed to be located between Cylinder 1 and 3 plugs but I can't seem to find it. Am I going to have to remove the alternator to find and access it or is my documentation not correct. Any pictures and instructions would be greatly appreciated.

 

 

could not get plug to budge. thinking of wiring fan 2 to always be on. Can't find anyone who can reprogram the fan to come on at 180 and off at 175. is the best way to wire the fan to come on when I start the car is to just jump the wires at the fan?

 

If you just ground the fan relays then they will stay on as long as the ignition is on. The terminals are D2 and F5 as per Rodjs info:

http://www.chevythunder.com/1994_lt1_ecm_pg_6.htm

A good quality socket (snap on) should ensure the plug comes out.

 

Being in sunny South Carolina where the temp's were above 100 this past week with high humidity, I know your concern. You can easily ground the relays so they are always on or you can run a wire from the relays to the driver's compartment with a switch on it (about $4 at Radio Shack) and then running the wire to ground. (I grounded mine on one of the master cylnder bolts near the firewall.) This way you can just turn it on when you want such as driving in town with stop and go or slow speeds. Of course, this means that you need to pay attention to the temp gage, but I trust you do this. Also, remember that the original wiring is not replaced so the fans should still turn on according to original settings including with A/C. The manual switch just provides a little reduced stress for those of us that aren't used to 230 degree temps. There are several posts on the Forum that describe installation of various switching options.

Also, you might want to check out the FSMs on CD that can be purchased on fleabay or elsewhere on the net. May not be quite as easy to use, but a lot cheaper than paper copies of the FSM and provide lots of lots of info, including wiring schematics, trouble shooting, etc. Really are invaluable if you plan to do anything or want to understand your car.

Happy Cruizin'!

 

Don't feel bad. JFB was giving me his "clairvoyant" speech too about not identifying the model year of my car in a thread I started. Problem was, he just didn't read my post closely enough cuz I did put it on there. I'm with you. This is a wonderful place to get to know people and to get to know about our cars, but people like him really need to lighten up a little bit, and give people some room to make mistakes as clearly, he makes them too.
JFB we still like ya but you need to COAR (Chill Out and Relax).

 

Hi guys,
I live in Florida and I don't have to tell you that it gets hot here. After many years of chasing ways to make my 94 run cooler to no avail I finally thought of cleaning the radiator fins of about 15 years of road grime and dirt. Without taking out the radiator was the trick as you really can't see the dirt outside of removing the radiator. There is a very small slot in the shroud on the passenger side of the housing that you can see into if you stick your head all the way down on the right side with a strong flashlight to look inside the housing. With a long nozzle insetacide sprayer I sprayer A/C coil cleaner (any A/C supply house has it about $20 a gallon.? onto the fins through this small slot being careful not to bend or even touch the fins and also through the opening on the fan side of the radiator. Let it sit about 5 minute ( not longer)and you will see a light smoking on the coil fins as it eats up the dirt. With the same sprayer now filled with water, I sprayed the cleaner off thoroughly (just hose off the radiator from the back side facing the front of the car, stick the hose between the fan blades. . You can't believe all the dirt that came off those coils. I know some will say that the caustic cleaner will damage the radiator but it is not left on long enough to do any damage. The car now runs at 193-195 in most normal driving situations and in really hot stop and go traffic it will go up to arounf 225 or so. That temp is a normal operating temp for an LT-1 engine. Please don't answer back with any rants about the wrong way to do things as all I know is it worked for me and I don't know anybody that loves there car more than me.

 

GM conducted hot weather testing on the Vette and there was never a cooling problem. Nor were there long lines at Dealerships with overheating complaints (except for the '85 wherein those who were autocrossing and climbing Pikes Peak complained about boilovers so an Aux fan became a Dealer installed option for that Year). If it doesn't work, it isn't the fan(s) - unless of course it isn't coming on at all - or it's slowing down and not moving enough air because there's some electrical issue.

 

I fought the cooling battles for 20+ yrs and tried everything in the book...with mixed or fair results. The concern was that "normal op temps" were too close to the edge...when something happens like a major hose break and you;re trapped in traffic, you can keep running it till it seizes in about 90 seconds or less while trying to fight your way across lanes of traffic, or shut it down in the left lane and BE the 6:00 news, or NOT place yourself in that situation at all..

I opted for 'C'.

Buying a REAL radiator is the answer. An all aluminum with bigger tanks and better heat exchange keeps the temps down enough to buy time in the event of an emergency. Its 103 here today and sitting in traffic with a/c going mines idling at 210. Freeway cruising at 195. Perfect.
Last yr with the stock radiator...that was idling (sweating) at 240.

 

I couldn't agree more! Get yourself a dual core all aluminum Dewitts drop in radiator w/ 40% more cooling capacity. That will be the end of your cooling issues. All w/ OEM fans settings and thermostat.

These C4's run waayyy to hot, your vette will thank you!