Tag Archives: green wire

Advisory: Failing Radiator Fans in Jeep JKs

My Jeep had been sitting in the garage for maybe a week.  So I decided to start it up one day, and was greeted with a new chime, and the dreaded Check Engine Light.

I ran my diagnostics through the Bully Dog, and the result was surprising – it returned codes for P0113 – Intake Air Temperature Sensor Circuit High, and P0480 – Fan 1 Control Circuit.

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I forced the fan on via the Bully Dog, and nada.  As a friend of mine recently replaced his fan assembly, I figured I was also looking at a $120 bill and 10 minutes of work.  Well I was wrong.  He has the 3.8l.  The new fan (OEM replacement) is a whopping $500 and very hard to find in stock.

With my wedding approaching (and the Jeep playing a key role in it) I was desperate to find out what was happening.

  1. Fuse and relay check.  I purchased some new fuses, and replaced it.  I ensured all relays and other stuff was firmly seated.

2. I inspected all wiring for abrasions and issues.

3. Last, I went on eBay and found a listing for a new fan for $300.

Before getting the new fan, a good friend came over with a much better understanding of vehicle electronics, and helped me further diagnose.

We soon found the problem!  There are 3 wires that comprise the fan harness.  Black is ground, red is hot, and green carries a signal between 9v-12v and that basically allows the fan to operate on a scale based on engine temps.  It isn’t a straight on/off fan.

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That little green wire had some sort of a short in the connectors.  We disassembled the connectors, reseated everything, and put everything back together.  I cleared the codes, and it has been great ever since.

So, before you panic and replace a $500 fan, check your wiring!

PS.  To the eBay seller in Miami that graciously let me cancel my order, thank you!!!