Hey Guys,

I apologize if I'm making a repetitive thread if there's one that's already answered. I did read through a bunch, but none of them seemed to elaborate on a situation like mine.

I have a 88 Trans am, 305 Carbureted. From what I know the previous owner took off the stock EFI/ fuel system (or whatever, I'm new to these cars) and stuck on a Holley carb.
The single cooling fan only turns on via turning on the A/C selector in the interior, assumably because there's no ECM control now.
I don't want the fan always on with the ignition, specifically for when I drive it in the winter. How would I get this thing to cycle with engine temperature, but also turn on when the A/C is on?
I found this dirt cheap thing on eBay: https://www.ebay.com/itm/Electric-Ra...d/112960325449 I don't know if this is too sketch, or how to have that control the fan, with the addition of A/C.

Thanks!!

 

Since the fan works with AC on that would indicate that almost all of the stock fan system; fan, fan relay and connected wiring is good. You need to see if the green with white stripe wire that should connect to the fan switch is intact and connected to the fan switch in the pass side head. If it is, the fan switch may just need replacing. They are a common failure point. Here's an article from the How-tos section found at the top of the page to explain how it should all work. Check it out, there is lots of good info in the how tos. Should be pretty easy to get what you want. Have fun!
https://www.thirdgen.org/electric_co...ec_mod_single/

 

How's it going? Was that stuff any help to you?

 

Hey, I just read through the post you linked, very helpful but a little overwhelming with so many details, haha.

So the conclusion I came to is that, I want to put a 170 degree thermostat in, and I think I want to put in the Hayden 3647 fan control. I still want the fan to always be on when the A/C is on though, Is that possible?

Also, I think I spotted the stock fan switch on the passenger side of the engine, which isn't connected currently. It guess I could try hooking that up again, but I don't exactly want the engine running at stock temperatures.

Thanks for the help!

 

There are many better options. The one that has lasted way longer than stock or aftermarket replacement ones is the Jet switch. Here's a link
https://www.jegs.com/i/JET-Performan...tent=Message+1

 

Upon grounding out the green white wire, the fan didn't turn on. So I guess I need to find a diagram of the factory system and check everything. The connector for the switch was cut off

 

You did that with the key on, yes? Since the AC on signal connects to the same wire to ground out the relay and operate the fan, there must be a break in the wire from the switch area to the relay. Check continuity on that
wire

 

Yes, I did it with ignition on.
So it appears that there isn't a wire going to the switch at all. So I should just have to run a wire to the relay and splice it to the green/white wire?

 

That should work. You can make sure by grounding it when finished to make sure it turns on the fan. Try following the green with white stripe wire from the relay to see where it goes. That may give you a place to tie into

 

I tried to find the OEM wire in the harness, but I had no luck. So I spliced a cable near the relay and ran it over the passenger side of the block. I ordered that Jet fan switch, then I should be set!

 

Cool, if you tested the new wire by grounding and the fan works you should be good. Fan switch comes with connector too.
Have fun!
Make sure the wire it secured safely away from the exhaust manifold and pipes...

 

So, is everything good now?

 

Yes! I installed the 170 degree thermostat and fan switch; It's working great! The fan turns off and on when needed, it's great.

Thanks for the very valuable help!

 

COOL, good to hear!