Parts only apply to pre-94 Magnas!! The new ones use a grounded switch.
That said, the basic procedure still applies. If someone knows a replacement fan switch source and part # for the third generation Magnas, please let us know.
I have an '85 V65 Magna on which the cooling fan switch died once again, and rather than pay Honda $150 to get it replaced, I decided to do it myself.
Tools:
- Most of the tools needed can be found in the standard toolkit.
- A 21 mm wrench (or deep socket if you use an impact wrench) needs to be supplied
- a crimp tool for the electrical connectors.
- Drain pan and container to dispose of old coolant.
- Adjustable wrench, depending on the nut size of the replacement switch.
Parts:
- Robyn Lander's Honda V4 files
- less expensive switch alternative ($15-$30 rather than $60) designed for Honda's cars. I got a Wells SW504 cooling fan switch for a '91 Honda Civic ($16, Western Auto/Parts
America). It switches the fan on at 92°C and off at 87°C. This is slightly lower than the '85 OEM part, but Honda uses the same range on the newer models as well.
- .157 blade female snap receptacles (18-14 gauge) to fit the new part, and 18-14 gauge tabs to fit the old wiring harness: the Civic switch has a bayonet fitting, while the original has tabs.
- A short length of 16 gauge insulated stranded copper wire.
- Electrical tape or silicone grease
- Fresh coolant (50-50 mix of antifreeze and de-ionized water)
Steps:
- Remove the left side radiator cover.
- Drain the coolant through the frame drain hole and the front cylinder drain plugs. First remove the plugs, then take off the radiator cap. The radiator cap is held in place
by a little screw in the edge of the cap. Make sure you keep an eye on it because disappears very easily... After draining, reinsert and tighten the plugs.
- Remove the old switch with a 21-mm wrench. Here it got tricky. Mine was stuck and even 2 days treating with WD-40 didn't help. The problem is that the radiator material is so thin that it starts to buckle the moment you put pressure on a crescent wrench. In the end, I bought a 21 mm deep socket and borrowed a friend's impact wrench. The switch came loose immediately without damage to the radiator.
- The new part comes with an O-ring seal, so there is no need to salvage the old one. The old switch carries a plastic snap pin that locks onto the plug. I removed it and connected it to the plug. That way, I'm not missing any parts if I ever go back to an original tabbed switch.
- Insert the new switch. The Civic part has a larger nut than the original,
so I used an adjustable wrench to tighten it.
- Cut two 1" to 1.5" pieces of electric wire and strip the ends. On each piece, crimp a snap receptacle on one end, and a tab on the other.
- Slip the receptacle ends on the switch, and insert the tabs in the old receptacle. It doesn't matter which pin on the switch is connected to which slot in the connector. The switch isn't polarized or grounded. Cover the receptacles and the old connector end with electrical tape or grease to prevent moisture from getting in.
- Refill the coolant through the radiator cap. Don't forget the little screw.
- Put the radiator cover back on. The new wires should have just enough flex so you can fit the old connector inside the cover, with no loose ends dangling outside.
- Start the bike. Check for leaks and make sure the fan comes on when its supposed to (this may take a while idling. If you don't see any leaks, take it for a short stop-and-go ride.)
That's it. This was my first project on the bike, and I got it done in about
30 minutes (excluding the time needed to locate an impact wrench.) Last time this
happened, the local dealer charged me two hours of labor "because to get to the
switch you need to take the whole front end apart". Hmmm...
I managed to get the part, socket and a Clymer's manual for less than the cost of the OEM part, plus I saved two hours of labor. Even if the Civic switch lasts only as long as
the OEM switch, the next one will only cost $16 instead of $150.
Thanks to member Sven Coenye (MRA #101) for this tip!
And for those on a real tight budget: bypass & hook up the fan to come on once engine is started. Stays nice & cool. Haven't had any problems with this set up....
Thanks to member Gary Peters (MRA #1481)
