[mjdwyer23]

Hi Guys-
I posted earlier regarding my questionable fan wiring. Upon looking into it closer, I am wondering if the previous owner wired the fan correctly. I have taken pics (to the best of my ability) of the situation:
Instructions for Zirgo fan:

My wiring, viewed from top of relay down (please pardon my handwriting):

The other wire on the fan itself goes to a 30a fuse to a battery junction block. I am looking at this issue because the car overheated the other day, and I found two 32V 30A glass fuses melted to their plastic holders where the wide blade 30A fuse now sits. When the ign is on and the relay wire to the fan is manually grounded, the fans kick on and the fuse blows almost immediately. Can anyone point me in the right direction? THANKS!

 

[bikeron]

Your wire size looks way too small for 30A.

The small wire will cause a lot of heat which can make your 30A fuse act like a 20A fuse. It might also explain your fuse holders melting.

The wiring they show is questionable. You could have a relay fire the way they have it drawn. The relay would need it's own fuse of a much smaller value.

Ron

 

[mjdwyer23]

The 30A fuse to the battery is 12 gauge wire (not pictured). Is that too small?

 

[bikeron]

The 30A fuse to the battery is 12 gauge wire (not pictured). Is that too small?

For 30A, it's a a little small. You notice they ask for 10 AWG in the directions.

The wires that carry the fan current to the relay have to be 10AWG also. Based on the color of the quick connects the wire is too small.

Can you sate what size wire is being used through out the system?

 

[mjdwyer23]

Cool. My question is, why is the 12v fuse box to the relay needed when the other connection on the fan is directly to the battery, or vice versa?

 

[bikeron]

Cool. My question is, why is the 12v fuse box to the relay needed when the other connection on the fan is directly to the battery, or vice versa?

You need the fuse as close as possible to the energy source. If a short occurs before the fuse (between the battery and the fuse) you have an unprotected circuit which could cause a fire; a lot of smoke at a minimum.

So right out of the battery connection you should have a fuse.

What is the current rating of the fan system?

 

[bikeron]

Your diagram is incorrect!. It looks like your running your fan current through the thermostat!

Terminal 86 should go to the thermostat (to ground)
Terminal 85 to the Fuse
Terminal 30 to the FAN
Terminal 87 to the Fuse
Ron

 

[mjdwyer23]

Supposed to draw 12-15 amps. Rechecked wiring from other side to battery junction, 10 gauge as suggested. 30 amp fuse instead of 20 amps.

 

[bikeron]

Supposed to draw 12-15 amps. Rechecked wiring from other side to battery junction, 10 gauge as suggested. 30 amp fuse instead of 20 amps.

Can you get a picture (close up) of the bottom of the relay?
I need to see the terminal numbers. Can you tell me what each terminal is hooked to also?

Ron

 

[mjdwyer23]

Yep, BRB

 

[mjdwyer23]

Relay labels (top left corner reads 86 and is tough to see):

Red goes to fuse box with 20a fuse
Wire on right goes to fan
Wire on left goes to temperature switch
Wire in back goes to ground

Other wire to fan is 10g with 30A fuse to battery junction block

 

[mjdwyer23]

Verbal descriptions describe top picture, not underside with connections. Sorry!

 

[mjdwyer23]

Also, for the future, how does one match up the relay description to terminals?

 

[bikeron]

Verbal descriptions describe top picture, not underside with connections. Sorry!

It looks like it is wired wrong. I need a picture where I can see the numbers on the bottom surface of the relay.

 

[mjdwyer23]

more info:
87: Fan Ground
30: Thermostat to ground
85: 12V to fuse box
86: wired ground

So, 85 and 86 are activating the relay when the ignition is on, and 30 trips 87 to activate the fan at x temperature. The fan power wire is currently wired to the battery with a 30a fuse in line, which blows when 30 to 87 is grounded manually.

 

[Dean]

 

[mjdwyer23]

So, should I re-wire the relay such that the fused battery + is running through it instead of the fan's ground?

 

[bikeron]

Also, for the future, how does one match up the relay description to terminals?

For a simple explanation of all this go to:

http://www.eurekaboy.com/f250/relay101.htm

You need a datasheet and part number to determine what the relay can do and how it is configured. If you can get one good datasheet it will help a lot as most automotive relays are built to an SAE ISO standard (so the terminal numbers are consistent from one manufacturer to another, but they are hard to get. Go here for an example:

http://rb-aa.bosch.com/boaarocs/ind...DBACAAC4EEBFB84.sundoro?ccat_id=31&prod_id=47

Relays are far more complex than most people know.

Here is how the proper wiring would go:
If you follow the rules than are specified by SAE, 30 always is supposed to go to the "hot" side from the fuse. 87 is the output to the fan. 85 goes to ground through the thermostat and 86 would go through a 1 amp fuse back to the battery.

 

[bikeron]

more info:
87: Fan Ground
30: Thermostat to ground
85: 12V to fuse box
86: wired ground

So, 85 and 86 are activating the relay when the ignition is on, and 30 trips 87 to activate the fan at x temperature. The fan power wire is currently wired to the battery with a 30a fuse in line, which blows when 30 to 87 is grounded manually.

Yep. wired wrong. You might have smoked the thermostat

Ron

 

[mjdwyer23]

I think I'm gonna pick up a new t stat and relay and re-do this with the fused battery feed for the fan through the relay instead of the ground.