Hello All,

95 Camaro LT1 installed in 89 RS Conv.

I have had the car running for ~6 months. Currently I have a manual switch for the fan relay control. Somewhat unreliable, because I have to continously monitor the car temperature. Just something unecessary to worry about.

Would like to keep the manual switch for race/autocross override but have the fan relay be automatic for daily driving.

I have searched this page and think I have everything in line. I just don't know what to connect to what....

Thing is this part of the install requires the engine to warm up to troubleshoot. I'm hoping I can get some clearifying answers and do it one time.

First I tried to identify the C100 plug. Please confirm visual with the attached picture.

C100. It's connected to the underhood fuse block.
|A|B|C|D|E|
|K|J|H|G|F|
| |
F is BRN and is power feed from FANS/SOLs Fuse 6
H is DK BLU and is secondary coolant fan relay control
J is DK and is primary fan replay control.
(ref mat89rs 1st post on LT1 wiring for dummies) Thanx!

2nd I have identified the PCM pinout relay control.
A is RED PCM connector
A11 dk grn Cooling Fan Relay Control
A10 dk blu Secondary Cooling Fan Relay Control
(ref Trans Am#5 14th post on LT1 wiring for dummiers) Thanx!

3rd I have included pictures of two sensors. One showing a sensor at the front of the block, mounted to the water pump housing. Another showing a sensor mounted to through the side of the block near the exhaust manifold (driver's side). Would someone explain how to wire the fan relay to be activated by the engine temperature?

Thank You,
Gus

 

Sensor is on front of block. Water pump housing

 

One green wire.

 

Are you using an Lt1 fan setup or the stock 3rd gen stuff?

 

Since you have an RS I'm assuming you've got a single fan. Are you putting the 4th gen dual fans in or leaving it single?

Single fan:
Trace the fan control signal from the fan relay back as far as you can. Trace the primary fan control signal from the PCM as close to the other wire as you can. Splice together.

Dual Fan:
Same procedure twice.

That will reenable automatic control of the fans. I think the easiest way to have manual control over the fans would be to use a dual pole switch with the PCM signal on one side and 12V on the other. When the switch is in the PCM position, you have automatic control of the fans; when its in 12V position, you manually turn the fans on.

 

Thank you for the info.

Basically all I need to do is take the manual on signal wire and splice it to the primary fan control pin/wire from the PCM. I don't use any of the sensor wires that I posted pictures. Glad I asked.

Now that I know I will work do some more research on the automatic control and manual over ride. I don't quite get the dual pole switch. I'll need to look into it. Then ask questions if I'm still unsure.

Thanks Again,

Gus

 

No problem gus.

You are partially correct on the sensors. If I remember correctly, the sensor in the water pump is what tells the computer the coolant temperature, whereas the sensor in the head is connected to the temp. guage.

As far as the switch, I'll see if I can explain it a little better. Its called a DPDT swith, which means there are 3 positions as opposed to two on a regular SPDT switch. On a normal rocker or toggle switch, you have an on - off movement of the switch. On a DPDT switch, you get on - off- on, allowing two different options on the same switch, perfect for an application such as what you want to do. I'm no electronics expert or anything so there may be a better way to do it, but that was the easiest way I thought of.

Any more help that you need, let us know.

Tristan

 

I tried taking the primary fan control signal wire from the PC and wiring to the fan relay. I let the car warm up to ~220deg on the third gen temp gauge. The fan never came on so I was getting nervous and just turned the engine off. I tested the signal wire from the PCM and was getting nothing. I am expecting a 5Volt signal from primary fan control wire.

I wonder if I am using the correct signal wire. Every documentation I see indicates the A11 or Red11.

Should I just wait longer? When should I expect the fan to come on?

Gus

 

This is what I found after checking out camaroz28,

"With the stock 180* thermostat the fan turn on points are 226 for the low speed and 235 for the high speed."

Maybe try waiting just a little bit longer. Do you a scan tool or any way to read the PCM while running? That would definitely help because then you would be able to see the temp the computer is reading and know for sure what temp the fan turns on.

 

Thanks very very good idea.

We have to find the scan tool. Been missing in action for a few weeks. But I will try letting in go a little longer. Just way higher than the old TBI would get before the fan came on. The other thing is the temp gauge may not be exactly correct.

Thanks Again