Z28Camaro30Ann

iTrader: (15)

I know, I know...I am having a lot of cooling issues lol. Ok, I have been trying to diagnose a fan problem for a while now and I am stumped. I am not good at reading schematics or diagrams so I need a little help here. This is what is happening...

Nothing............at all. Nothing when it reaches temp, nothing when I turn the car on or off, nothing when I unplug sensors, nothing when I jump relays, nothing when I turn on my SLP fan switch...They only turn on when I apply DIRECT power to the fans themselves...

This is what I have tested so far...

I have constant hot at the 10A fuse in the fuse box.
I have constant hot on 1 pin EACH on Relays 1 and 2, NO constant hot on relay 3.
I have good ground on all 3 relays
I have good ground on the pigtail to each fan
I have power on 1 pin on Relay 3 when I turn on the fan switch.
Coolant temp sensors are reading according to dash gauges and my laptop
Fans are set to turn on at 180/190
I can apply direct power to the fans and they turn on
I have traded out all 3 relays with the fan switch on and nothing happened

I have been trying to read the diagram linked below, but I am VERY bad with them, so I have only learned a little bit from it...I know that Relays 1 and 2 should have a constant hot wire, but does Relay 3?? Also, I just now learned what wires signal the fans to turn on from the PCM, so I am going to check those in a minute, but Other than that I am at a complete loss...

http://shbox.com/1/fan_schematic_1995.jpg

Also, I have converted my PCM from OBD2 to OBD1...I THOUGHT they worked properly after the swap but I can't remember 100% if they did or not...is there any problems with this setup and the fans or should it work fine? I know the 93-95's use a 2 Relay system and 96-97 use a 3 Relay system...

shbox

No, relay #3 does not have a constant +12v supply.

Try this... Unplug C100 on the shock tower. Rig up a ground wire for testing. Touch the ground wire to pin J (dark green wire) toward the front of the car. Both fans should run at low speed. Remove ground from J and touch it to H (dark blue wire). The RH fan should run on high speed (the LH fan should not run). Touch the ground to H and J at the same time and both fans should run on high speed. If all that works, there is no problem from that side of C100 to your fans.

Mid 94 is when they went to 3 relays for low/high speed fans. The 2 relay system was used to run LH and then also RH fan, but both at full speed.

Z28Camaro30Ann

iTrader: (15)

I will do that first thing tomorrow.

So this PCM from a 94 Camaro is a match for the fans then correct?

shbox

Yes, it is.

Z28Camaro30Ann

iTrader: (15)

Ok, so I put my relays back in, and grounded pins J and H on the connector towards the front of the car and nothing happened at all...I had the key off when I did this...is the key supposed to be on or off?

shbox

The key should not have to be on for 96-97s (earlier years, yes). You already said you were getting constant power to the relays like you should. It appears you need to check continuity from C100 to the relay sockets. Grounding the leads as I suggested should operate the relays.

Z28Camaro30Ann

iTrader: (15)

Ok, so now for my next question. I am considering temporarily bypassing the current system to operate my fans manually and safely. I am thinking about running a fusible link from a dormant fuse in the fuse box, to a relay, to the fans and the trigger will be a switch in the ashtray. How do I rig this so that it will activate both fans on high when I flip the switch, and am I able to use one of my dormant ABS fuses for this and just throw in a higher rated fuse for the relay power?

shbox

The best and safest way to operate the fans is by the existing system. Fix it, first. Then you can use a fan switch like is diagrammed on my website.

Z28Camaro30Ann

iTrader: (15)

Ok, so the dark blue and dark green wires run through the harness around the front of the car and into the fuse box to the relays correct? How do I test these to see where the disconnect is? Do i need to get it to operating temps and test them.for power from the PCM or can I simply turn on my SLP fan switch and start testing there? Doesn't the SLP switch use the same wires for the trigger?

Big Al

iTrader: (1)

I would start by unplugging both fans and running them with a jumper wire. You need to start somewhere and work back.

BTW: On my 95 the fans won't run unless the engine is actually running.

Al 95 Z28

Z28Camaro30Ann

iTrader: (15)

Before this started, I could turn the fans on with my SLP Fan Switch with the engine off. Now I cant...I have ran the fans on a jumper and for the record, BAD IDEA because I burned a fan motor up doing that. You NEED to have them fused an on a relay to avoid destroying a motor. I know I have power and ground at the relays, and I know the SLP fan switch is getting a signal TO C100. Doing what shbox says does not turn my fans on and I know he knows more than just about anyone on this site when it comes to this stuff so if he said they should turn on, I believe him...but they didnt so something is wrong between C100 and my fuse box. If I am right, I SHOULD be able to activate my SLP Fan Switch and test the trigger socket on my relays in the fuse box and they SHOULD be getting a hot. I know Relay #3 gets a hot when I have the switch on which tells me that the dark blue wire is getting good continuity to the fuse box...I guess I need to focus on the dark green wire and see if it is getting a signal to the fuse box eh? lol

Z28Camaro30Ann

iTrader: (15)

OK, here is what I came across while checking voltage in my fuse box. Maybe someone can translate this for me.

I hooked up my SLP Fan Switch and tested continuity and voltage on each setting for each relay. I left each relay in place EXCEPT for the one I was currently testing voltage on so that the signal was not interrupted. Here are my findings: (I go by wire color on the SLP Fan Switch because I am not sure which one is high and which is low...there are 3 wires, red, white and black....obviously I know black is ground...)

White Wire ON:

Relay #1:
Pin 1 - 12.57v
Pin 2 - 0.00v
Pin 3 - empty
Pin 4 - 0.00v
Pin 5 - 12.57v

Relay #2:
Pin 1 - 0.00v
Pin 2 - 12.56v
Pin 3 - empty
Pin 4 - 12.56v
Pin 5 - 11.67v

Relay #3:
Pin 1 - 0.00v
Pin 2 - 12.54v
Pin 3 - 0.00v
Pin 4 - 0.00v
Pin 5 - 11.65v

Red Wire ON:

Relay #1:
Pin 1 - 12.56v
Pin 2 - 12.56v
Pin 3 - empty
Pin 4 - 0.00v
Pin 5 - 0.02v

Relay #2:
Pin 1 - 0.00v
Pin 2 - 12.56v
Pin 3 - empty
Pin 4 - 12.56v
Pin 5 - 12.56v

Relay #3:
Pin 1 - 0.00v
Pin 2 - 12.56v
Pin 3 - 0.00v
Pin 4 - 0.00v
Pin 5 - 12.56v

Can anyone translate this for me and tell me if this is correct or if something is not reaching the fuse box?? Pin 5 on Relay 1 of the red wire has me a little bit nervous but honestly I have no idea how to read relays or what is going on here....I am helpless when it comes to wiring. I am sorry if this sounds stupid or basic, but I can't figure it out!

Z28Camaro30Ann

iTrader: (15)

I am looking at the diagram for the fans listed above and here: http://shbox.com/1/fan_schematic_1995.jpg

Using the readings I took above, I have come to THIS conclusion...

The dark green and dark blue wires transmit the signal from the SLP Fan Switch connectors TO the Fuse Box with full current, so there cannot be a break in the trigger wires between C100 and the fuse box...

I have swapped out the relays with every relay in the fuse box and still nothing but what I am reading from this is that the relays are out.....is it possible that ALL of my relays are dead somehow??? I think I am just going to buy 3 brand new relays and give it a shot...

Z28Camaro30Ann

iTrader: (15)

After some help from a good friend, it turns out that the ignition wires that power the relays when the key is on, no longer had power when they were supposed to. I fixed it and they work perfectly now! Thanks Bobby and thanks to shbox and everyone else who helped me out!

PROBLEM SOLVED!

shbox

From earlier reading perhaps I was mistaken in thinking that power was ok. If I had thought it was not, I would have suggested you check it. According to schematics, the key should not need to be on (96-97s only). Anyway, glad it is back working.