fan wiring questions
Get control of your relay coils. If you can't control your relays nothing else matters.
Disconnect all of your PCM wiring if you have to. Via the diagram, only 12V on pin 85 (I actually recommend switched 12v). You've got to get control of pins 86 on all three of your relays. Remove any wiring you have on pins 86. Whatever is connected to them is wrong. Tie a length of wire to Relay #1 pin 86 that's long enough to manually touch it to chassis metal. Tie a length of wire that branches to both Relay #2 and #3 relays pin 86 that's long enough to manually touch chassis metal. Finally install your relays. If any of them click when you insert them into the socket, something is wrong. Relay 1 should only click when you touch the wire attached to its pin 86 to ground. Relay #2 and #3 should only click when you touch the wire attached to both 86 pins to ground.
There's nothing else to do. You've got to get control of the relay coils. Focus on pins 85 and 86 and get them working like I described above. Take everything apart if you have to. Isolate the problem and get the relay coils under control. I can't do anything else for you until that's working right.
Lane
Thread Starter
Staging Lane
Joined: Nov 2015
Posts: 82
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::::update:::
Found my problem
These are the relay, Im using:
HELLA 007794311 (great relays)
These are the relay harness i choose to use (because of the ease of install)
Here is the problem, the wires on the harness are labeled with number 1-5 that correspond with the numbers on the relay pins, or so i thought. 5 wires, 5 pins on the relay, 1-5 written on the wires. you would think that these numbers would correspond with each other,
well ladies and gentleman they don't, they don't correlate with each other at all.
so what did we learn from this thread,
1. how to diagnose a wiring problem, thank you lane
2. assumption is the mother of all actions.
Found my problem
These are the relay, Im using:
HELLA 007794311 (great relays)
These are the relay harness i choose to use (because of the ease of install)
Here is the problem, the wires on the harness are labeled with number 1-5 that correspond with the numbers on the relay pins, or so i thought. 5 wires, 5 pins on the relay, 1-5 written on the wires. you would think that these numbers would correspond with each other,
well ladies and gentleman they don't, they don't correlate with each other at all.
so what did we learn from this thread,
1. how to diagnose a wiring problem, thank you lane
2. assumption is the mother of all actions.
The only way you're going to solve this is to do some hands-on systematic troubleshooting to discover your wiring fault(s):
Pro tip before starting - Label your relays Relay 1, Relay 2, and Relay 3 according to the wiring diagram (your first post) and what your physical relays represent. Even if its just a sticky note. Get it all straight and stick to the same annotation while you troubleshoot.
You'll need a multimeter than can measure DC voltage and continuity:
Remove all three relays so you're only dealing with the sockets
DC Voltage tests:
1. Confirm 12V between the socket for pin 85 and the negative battery terminal on all 3 relay sockets
2. Confirm 12v between the socket for pin 30 and the negative battery terminal on relay sockets 1 and 2
Continuity tests:
1. Confirm continuity with the end of the dark green wire and the socket for pin 86 for relay 1
2. Confirm continuity with the end of the dark blue wire and the socket for pin 86 for relay 2 AND relay 3.
3. Confirm continuity between the socket for pin 87 for relay 1 and side B of the left cooling fan connector
4. Confirm continuity between side A of the left cooling fan connector and side B of the right cooling fan connector AND the socket for pin 87 for relay #2.
5. Confirm continuity between the socket for pin 87 for relay #3 and Negative Battery Terminal
6. Confirm continuity between side A of the right cooling connector and Negative Battery Terminal.
Do the steps in order and use the negative battery terminal for your connection when I specify to. Verifying at the negative battery terminal will ensure you're circuit is making a good connection to the chassis ground. If it doesn't make it all the way back to the battery, it's a crap ground and testing it my way will reveal the problem
Post results
Lane
Pro tip before starting - Label your relays Relay 1, Relay 2, and Relay 3 according to the wiring diagram (your first post) and what your physical relays represent. Even if its just a sticky note. Get it all straight and stick to the same annotation while you troubleshoot.
You'll need a multimeter than can measure DC voltage and continuity:
Remove all three relays so you're only dealing with the sockets
DC Voltage tests:
1. Confirm 12V between the socket for pin 85 and the negative battery terminal on all 3 relay sockets
2. Confirm 12v between the socket for pin 30 and the negative battery terminal on relay sockets 1 and 2
Continuity tests:
1. Confirm continuity with the end of the dark green wire and the socket for pin 86 for relay 1
2. Confirm continuity with the end of the dark blue wire and the socket for pin 86 for relay 2 AND relay 3.
3. Confirm continuity between the socket for pin 87 for relay 1 and side B of the left cooling fan connector
4. Confirm continuity between side A of the left cooling fan connector and side B of the right cooling fan connector AND the socket for pin 87 for relay #2.
5. Confirm continuity between the socket for pin 87 for relay #3 and Negative Battery Terminal
6. Confirm continuity between side A of the right cooling connector and Negative Battery Terminal.
Do the steps in order and use the negative battery terminal for your connection when I specify to. Verifying at the negative battery terminal will ensure you're circuit is making a good connection to the chassis ground. If it doesn't make it all the way back to the battery, it's a crap ground and testing it my way will reveal the problem
Post results
Lane
To edit, 85 on my relay is the pcm signal wire, so there is no voltage going to that.
So I started with your test above.
Voltage test:
1. On relay one and two, I have 12v at pin 85 but not on relay 3. Is this with the key off or key on?
2. For pin 30, I have no power for relay 1, but 12.x for relay 2. Again, this is a problem.
Continuity:
1 Dark green is good from relay to the pcm. Low speed fan.
2 Dark blue is good from relay to the pcm. High speed fan.
3 Good connection.
4 Good connection.
5 Good connection.
6 Good connection.
I've checked for popped fuses to explain why I don't have power, but I don't get it.
Last edited by The Alchemist; Aug 29, 2016 at 04:37 PM.
