I would really try to find and fix the root cause first. If you try to add a manually-controlled switch to the cooling fan relay, you will likely be driving around with the 'ck eng' light on.
This is something that should be under PCM control. The PCM may call on the TIPM to actuate the relay. A skilled diagnostician should be able to find and fix the real problem here.
This is something that should be under PCM control. The PCM may call on the TIPM to actuate the relay. A skilled diagnostician should be able to find and fix the real problem here.
