You guys were great on helping me with the opti and getting the car running,thanks again, so here is where I'm at;

While putting the fans back in I found the wires to them had been cut and the plugs were no where to be found.
I got plugs and wired them in, pluged them up, started the car and of coarse had to shut it down in order for it to not overheat. The fans never came on.
It got dark on me so I had to quit. Aside from powering the fans up directly with battery power (just to make sure they work) what else can I check?
I have checked the fuse marked "fan" in the box under the hood which was good. I know there two fan relays there also but I dont know how to test them.Also the po said her ex wired the fans to a toggle switch which I found one in the dash with wires that go thru the firewall pretty close to where the pcm is located but as I said it got dark on me so this is where i quit.

Can someone point me in the direction to getting my fans working as they are supposed to again?

 

The way the fans are supposed to work
1) ECT sensor sends coolant temp to PCM
2) Depending on temp the PCM con trolls the fan relays
3) Being that you mentioned you only have 2 fan relays, then the PCM first operates the main fan, and if temp still goes up then it operates the relay for the aux fan, and now both fans are working.
You can test the relays by substituting an equal relay from another circuit. If fans still do not work, then check wiring from ECT to PCM, PCM to relays, power wiring from fan fuse to relays, wiring from relays to fan. A wiring diagram would help a lot. Also the switch was probably put there because the fans were not going on, which means some wires had to be cut and need to be spliced back to original condition.

 

I may have misspoke, this is a '95 Z/28 with lt1. I seen where the diagram on the box had a space on each end marked "fan relay" I did not look any further, are there suppose to be more?

Sorry, I haven't got all the abreveations down yet, what is the ECT and where might it be located?

 

Since it is a 95 model it will have 3 fan relays.
PCM will command both fans on at LOW speed if coolant temp exceeds 226 deg F
PCM will command both fans at high speed if coolant temp exceeds 235 deg F
At low speed the fans will be connected in series, each fan getting 6 Volt
At high speed the fans will be connected in parallel, each fan getting 12 Volt
PCM energizes relay #1 to connect fans for low speed (gnd on green wire to #1 relay)
PCM energizes relays #2 & #3 to connect both fans for high speed (gnd on blue wire to relays #2 & #3)
PCM also looks at road speed via the VSS and turns off fans after a certain road speed is reached.
Fuse #6 provides energizing power to the relay windings
A fusible link provides battery to the relay contacts
PCM connection: Connector A (red) pin 10 blue wire, pin 11 green wire
PCM receives temp data on Connector C (clear) pin 25 yellow wire


Hope this helps.

 

Very good, Pete.

 

ect/engine coolant temp sensor is on the front of the water pump

 

Any way to test the ect? So far I know the relays (all three) are good and using a jumper on the fuse/relay block 30 to 87 = nothing on relay spots for coolant fans #1 and #3 but does make the fan run on coolant fan #2. Any direction on what and how to check/test anything else would be great.

 

yes brb

 

get the ohm meter out and get er done
4th Gen LT1 F-body Tech Articles

more info
4th Gen LT1 F-body Tech Articles

 

Back at this again. The test did reveal a bad ect so that has been replaced.


The problem I'm having now is that it's puking coolant out the reservoir. This doesn't happen when the car is started, it happens about 12min after the car has been started and idling and the temp is around 215-220. I shut it down, there is a lot of gurgling going on until I release pressure at the cap.


There is no presence of oil in coolant or coolant in oil so I don't think anything is cracked or blown.


Any idea's on the matter are greatly appreciated and will be investigated thoroughly