I have a 93 z 28 with an auto. I have removed the A.C. compressor , ABS an installed a new rebuilt auto trans. Now the cooling fan won't come on untill its way to hot. What have I done ?

 

What do you mean by 'too hot'? The cooling fans would normally come on at 226 degrees. In your case, with a 93, one fan will come on at 226, then the second at 235 degrees. That temp is right around the 3/4 mark on the dash gauge.

 

250 ish too hot. An when I turn the A.C.. on the fan won't come on iether. I'm assuming its because theres no line pressure.

 

i looked at shoebox's website and it says that the 1993-1994 (early 94) fans come on at one temp 235 at one full speed

 

The fans in those model years have only a high speed. One fan will come on at 226, then the second will also come on at 235 if that temp is met.

 

I might be mistaken, but I believe the in later years- the high speed fan would come on automatically when the a/c was turned on as long as the motor was at least at operating temp. This was in anticipation of the added load on the motor from the A/C- not having line pressure should have nothing to do with the fans not coming on since they are controlled by the ECU. But GM did some weird things in the 93 early 94 years too so I can't say for sure.

Double check your fuses and relays- could be something that simple that also happens to be a coincidence.

 

The eaisest way to "fix" the problem would be to hook them to a toggle and turn them on when you want

 

Tsk, tsk....It doesn't say that.

It clearly states
Primary@226º Primary (LH) fan full speed
Secondary@235º Secondary (RH) fan full speed


HRE, your fans won't come on with the a/c because the a/c is not functional. It could be that your gauge is indicating a little hotter than it is or that the time lag for the fan operation is letting the temp creep up. A scanner will tell you when the fan is commanded on and you can check that against the temp the scanner is seeing.

Or...you can get some reprogramming done to your fan temps or add a fan switch.

 

I am having the programing lookedat. Thank you for the replys. Everyone has been helpful. Thanks again.

Question - Could I alter the a.c. wireing to foul the into thinking it is functioning ? Or would something like this make the fan constant ?

 

Get the fans to work right WITHOUT the A/C, rather than trying to make them work by fooling the PCM to think the A/C is still there.

 

The pcm coolant temp sensor might be disconnected.

 

If it was, the fans would be on all the time and he would have a check engine light.