Coyote cooling issue

[CalR80]

Hi All,

While driving to the Huntington Beach show in April I got a nice dose of LA traffic
The hot weather and traffic combined had my Mk4 Coyote start to get pretty hot. I pulled over and discovered that the cooling fan was not coming on. The PDB box showed the green light on for cooling fan but alas, no fan came on. I found an Autozone and was able to directly wire the fan to the battery with a bit of Jerry rigging. We made to Huntington a bit late but had a great time at the show. Made it back to San Jose and figured it was probably a bad connection to the fan. Well, it wasn't and now I'm thinking it might be the fan relay in the Power Distribution Box. For you Coyote whisperers out there, could you tell me what relay controls the cooling fan?

[2bking]

The fan relay is the large black relay in the upper right corner of your picture. I'm not sure of your access to the PDB with it powered up so some of the trouble shooting may be limited. The coil of the fan relay is powered from the PCM relay. The PCM relay is energized when the ignition is "on" and provides power to the PCM plus the fan and start relay coils. The fan is turned on by the PCM by grounding the negative side of the fan relay coil. Having the fan LED illuminated indicates the fuse is good and the relay is working. When the fan relay LED is illuminated, there should be 12V on the fan connection stud, the one the large orange wire is attached to. If 12V is there then follow the orange wire to the next connection and so on. To trouble shoot this on a cold engine turn on the ignition and ground pin A-12 on the BEC connector under the large green cover. This will engage the fan relay and voltage on the stud can be checked. If the LED is on and no voltage is present on the stud, the problem is on the PDB circuit board.

Once the problem is solved and for some reason you want a manual fan switch, splice into the wire that is connected to pin A-12 and run it to a switch and then to ground.

[CalR80]

What a great explanation, thank you 2bking!

[initiator]

Another poster found that the one of the retention clips on the Coyote fuse panel was a little loose. He spend lots of time troubleshooting and eventually found that he had to pull out a fuse (or relay, can't remember) and bend the clips together a bit to make better contact. Reinsert fuse/relay and problem went away.