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Other Fan Relay?

4K views 3 replies 2 participants last post by  NoveSedici 
#1 ·
Hi,
From the 2000 ST4 wiring diagram kindly provided by Derek I see that there is an "Electric Fan Relay", number 10 in the diagram which is connected to the 7.5A fuse under the seat.
http://www.ducatiwiki.net/images/8/87/ST4_2000_Schematic.pdf
This relay is in addition to the two relays under the seat that control the fuel pump and cooling fans which are connected to the 20 A and 5 A fuses respectively.

Where is this Electric Fan Relay (identified as number 10) physically located on the bike?

My cooling fan does not come on as intended, but strangely, as the ignition is turned on, the fan runs for about 1/2 a second, almost like a relay contact is bouncing. I have replaced one of the under seat relays and then swapped them around and the fuel pump runs either way. All the fuses have been checked, but just can't find the other relay.

Before jumping into a fan relay bypass mod, I would like to get the system working as designed.

Thanks in advance,
Richard
 
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#2 ·
Richard, your linked schematic shows #10 as the water temp sensor (not a relay). The relay that directly activates power to the fan is #11 in the diagram and is located under the seat opposite the fuel pump relay. That is only relay to the fan. It is protected by 7.5 amp fuse as noted. If relay is activating intermittently, swap it out for new one. If that symptom persists, it may be caused by a short somewhere or ECU fault.
 
#3 ·
Thanks Vinnie, I meant #11. The two relays in the diagram under the #30 fuses are the ones under the seat, based on the wiring colors. the diagram clearly shows the relay at #11 and the left hand relay of the two being connected to each other and then to connection 35 of the ECU. Somewhere there is another relay in the circuit to the fan.
 
#4 ·
Found it

I finally found it. The second relay (#11 in the diagram) is under the left rear side cover and is protected by the 7.5A fuse. That relay is provided power by the left one under the seat which is protected by the 5A fuse. I replaced mine with a BWD R3223 from Advanced Auto for under $11.
 
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