My civic is repeatedly melting blower relays. Much of the cabin wire harness has been replaced after the wires next to the c440 connector shorted from being rubbed through, also replaced the fan switch, blower motor, blower resistor and heater control panel after that same harness failure(?) melted all of those.

That stuff was all replaced a month or so ago and everything has been fine but I just got back from a 3000 mile road trip and now this relay problem has cropped up.

Basically where should I be looking first because I can't find any more shorts.

 

Oh yeah this is on the 1997 CX Hatchback

 

Is this happening without blowing any fuses?

Hood fuse 55 should be 40A, and dash fuse 17 should be 7.5A. Do you have the correct amp rated fuses installed in those slots?

Is the correct relay installed?

 

the fuses are correct and not blowing and the relay is almost certainly correct as I borrowed the second one out of my other civic where it has been fine for some time.

 

Besides the melted relay, any problems at all with the blower or mode control motor?

 

Nope but the blower is only 2-3 months old

 

My guess would be that relay or hood fuse box is bad.

 

Can that be tested or do I have to just replace it and see

 

I'd remove the hood fuse box and inspect the underside for signs of burns or damage, especially the area under the blower relay socket.

 

UPDATE: at the time of this post I replaced the fuse box and relay as the relay has slowly melted again.

 

I am thinking you have a short, have you check the blower wiring, trace it back as far as you can get a wiring diagram.

 

My 2000 Accord has had this same relay melting problem 3 times. Most recently being today! I have opened all of them up (removed the outer cover) and each time the electrical "Contact Tab" has been completely separated from the copper swing arm. I am sure this is partly due to over heating and also due to too much pressure being applied to crimp the contact tab to the arm during production, thus weakening the copper join area. Luckily the Relay is only $8. I have been carrying spares in my glove box for the last 7 or 8 years, so whenever the relay fails, I am ready!! Tomorrow I will buy another replacement!!! Either the relays are defective, under-rated for this application, or the Condenser Fan is just drawing too much current.

 

My 93 del sol si had a corroded wire connector where it attaches to the fan blower motor. It burned the insulation around the connector and the blower motor would shutdown after 5 minutes of operation. The blower relay would get very hot during those 5 minutes. I replaced the fan motor the resistor and the relay. The new fan motor had a hard wire connected which I spliced in to my harness after cutting out the old worn out factory connector. Everything works great since. Del sol's get a lot of moisture condensation near the passenger footwell and it effects ECU's located there also.