i have a 96 trans am. i have verified with a scanner the dash gauge and computer temp are almost dead on with each other. the problem i have is no fans come on till 228-230 and it is only the drive side fan and i have to look with a flash light cause i can't hear it comming on but it does. when it gets down to 222 it turns off. i have a ac leak and the ac quit working several months ago so turning the ac on does nothing. i am trying to figure out why the passenger fan does not come on? i have replaced the relays and tested them by placing them in the fog light spot and the fogs work so i assume they are good. any fast way of testing the fans? i have jumped 5 and 6 on the odb 2 connector but did not hear them come on. i will have to double check this later but believe they did not come on as i only turned the key to the on position which is how i was told to do it. i am confused because the one seems to work fine. any help cause it gets hot setting and it gets almost to the red then comes down to the 3/4 mark on the temp guage. while driving it is about 180-190.

please help before i go insane. just bought the car and i notice this...

 

Maybe one fan motor is shot. Remove relay #2. Jumper between F4 and F1. The RH fan should come on at high speed. With all relays in place it should also come on when you ground the dark blue wire in cavity H of C100. If you can read a schematic, you can do troubleshooting of the circuits.

 

very good sir i had no clue where to jumper the relay socket. i can read schematics but i am also leary of frying something lol. i will give that a try. if the fan still doesnt dome on then i guess it is a fan motor or wiring to fan.

is the fan sold as a whole or can i buy just pieces of it.

 

ok i did the test you described on relay 2 and relay 1. both activated the fans on high. i have not grounded the 2 wires to see if they come on. is that a important test to see what is up? is there any other tests to help track down this issue? i am totally at a loss here. since this is new to me and i have had the car only a few days could it be a chip installed or something causing this? how can i tell

SO HERE IS WHAT I KNOW
1.)relays are good
2.) if i jumper at the relay socket on relay 1 and 2 the fans come on high
3.)dash guage and computer temp sensor are almost dead on
4.)jumping pin 5&6 on odb2 plug under dash does not turn either of them on (can't tell if it is doing anything with the key on, no lights flash or anything)
5.) only the driver fan comes on at 228-230 and shuts off at 222
6.)car runs about 180-190 driving down the road

 

Next test-Disconnect C100 and ground J only toward the fans. Both fans should come on at low speed. If that works, leave J grounded and ground H and both fans should run at high speed. If that is ok, your problem is from that point in the wiring back toward the PCM or in the PCM, itself (maybe even a pin problem at the PCM).

 

ok i did the test and had a friend help and here is what i found. grounding the wires resulted in just what should. got both low and hig speed. had a friend with a scanner and we watched to see what happened with it running. at 228 the fans kicked on low. i confirmed that both fans were on but it seemed like they were on low. never reached over 230 so i can tell if high speed works. it seems as though all is well but just getting warmer than i think it should. i am old school chevy and this just seems way to hot. on the old motors i got nervous anything over 205 and mostly they around 195. is a 230 temp ok for the lt1? My car when driving is just a needle width past the 185 mark. could someone put a lower temp stat in and cause this wild flux in temp range?

is this normal? what thermostat is in these from factory? i have read different temps that the fans come on. some say 212 and gm service manual says 225 for low and 235 for high. what is correct?

 

Lots of people, including myself, have installed manual fan switches to combat this problem. You can get ot from SLP or make one up yourself. The instructions are on either shoebox's or bret frankers page, dont remember.

This way you can just turn the fans on when your need them, i go to low as soon as i get into traffic.

Its normal for your temp to shoot up like that though, there isnt any airflow through the radiator untill high speeds are reached and the air dam moves it up.