so after checking out this 94z28 i picked up ive come to find out that the fans do not come on at all, and the ac is not working , i checked the fuses and buses and they are fine for the fans, i was reading the manual and was thinking about the engine coolant temp sensor , any clues that any of you guys have figured out. also the funny thing with the ac is the same, is has r134 in the lines but when i switch on the ac the clutch doesnt engage, but it also seems that the blend door might be stuck also cause it only blows on the feet no matter which setting it on. any help would be awesome.

 

ok ive read a few other posts and it seems like the fans just suck, im probably just gonna get the slp switch from summit, livin in phoeniux, when the car gets above the halfway point it starts boggin and backfiring , it has the lt4 hot cam swap, but it runs like butter n the morning and when its cool but as soon as it gets warm, runs like crap.

 

Dont let her get too warm unless you want to spend lots of cash. Heat will kill any LT OR LS series engine faster than any thing. If you have some skill you can hotwire the fans for a second to make sure they are working then you can truble shoot the problem. It could be a temp sensior or could be the damn fans just went out. I had a problem with my ls1. I ended up running a Switch inside the car this worked but it got old fast. Now I have it run to over ride the temp switch when i need to keep it on at the track. But when its off the PCM takes care of that.

 

how did you override it, i dohave some skill, mostly with carbed engines though, i was thinking it might be the engine coolant sensor because both fans arr not running. i know about the switch getting old, had one in my 86 iroc, ive read about the thermostat that makes the fans kick on earlier , is that a good buy?

 

my bad the fans do come on if thats what you want to call on, phuh. it gets up to 230 just sitting in my driveway. one thing that seemed kinda odd is that the radiator hoses were soft and hot, thermostat maybe?

 

Early builds used 2 fan relays, late builds used 3 fan relays, V6 use 1 fan relay.
Power for the fans comes from a fusible link, goes through the relay contacts, and then to the fan motors. Power for the relay coils comes from fuse # 6. The relays and the fuse are in the under hood electrical center. A quick check of the circuitry is to disconnect the plug from the ECT sensor (mounted on the water pump), strap a 100 Ohm resistor across the two leads going back to the PCM. This will simulate very high coolant temp and the PCM will order the fans ON. If the fans now go on, the ECT is bad, if not then there is a problem in the circuitry.
See attachments for fan wiring diagrams.