Cooling fan circuit breaker move

[nkemp]

The cooling fan circuit breaker is between the fan control relay and the fan fail unit. That means there are fan controller relay failure modes not protected by the breaker. For example if you use the wrong relay in the relay controller socket it can short 12Vdc to ground.

I propose that the circuit breaker should be before the fan controller relay, not after. Also there is no reason for the ground from the center prong. It is only a potential problem.

I have not made these changes yet. But thought I'd post it first.

[Bitsyncmaster]

The cooling fan circuit breaker is between the fan control relay and the fan fail unit. That means there are fan controller relay failure modes not protected by the breaker. For example if you use the wrong relay in the relay controller socket it can short 12Vdc to ground.

I propose that the circuit breaker should be before the fan controller relay, not after. Also there is no reason for the ground from the center prong. It is only a potential problem.

I have not made these changes yet. But thought I'd post it first.

That is true. Headlight relays also fuse the load side. I do recommend the center ground pins not be used (removed).

[hmcelraft]

That is true. Headlight relays also fuse the load side. I do recommend the center ground pins not be used (removed).

Why do you recommend that?

[nkemp]

Power flows from the battery to the relay and is unfused. The center lug in the relay socket is grounded. If someone puts the wrong relay in the socket it can cause a short circuit by jumpering 12Vdc directly to ground. If this happens the wires will heat up until they melt possibly causing a fire. By removing the possibility of grounding, you reduce the risk of a meltdown. By moving the circuit breaker to the other side of the fan controller the breaker would trip if it was accidentally jumpered.

[Bitsyncmaster]

Why do you recommend that?

My reason is the relays will pull from the sockets with less force. But as nkemp pointed out, if you stick a lambda relay in there it will burn up the wires.