Any experts on electrical issues / main relay on 83 VF750F

My Fans are not activating and I have tested and traced it back to what they call the main relay,it is 4 pronged...
I am getting no volts at the 10a fuse that feeds the fans couplers.Straight wired it and they work fine and I am getting
full voltage at the red wire feeding the going into the main relay..But its not activating the bl\bu wire that feeds the couplers..

Can I run\wrap a jumper wire on the main relay terminals from the red to bl\bu prongs and where can I source a replacement relay??
Thanks
Robert

 

If you post a picture/link to the wiring diagram, then I can help

 

+1 on this

I read the original post twice and I am struggling to work out whether you are saying the relay is defective? or that feeds to the relay are defective?

If the problem is simply that the relay is defective and you want to find a replacement, then if Honda cant help, its worth remembering that inside it is probably a standard 4 pin relay so I suggest you take it off the bike and show it to the parts person at any decent motor-factors and they will probably be able to supply something which will do the job - even if the part says GM!

If however you have checked the relay and confirmed it works fine, then it suggests the trigger side of the relay is not going live when the fans need to operate. That is however when things get difficult to offer any sensible advice without actually seeing a wiring diagram for that model bike.




SkiMad

 

wish i had the diagram for that year, but no prints for me

 

Is this your only bike or a project bike? I will be getting mine back beginning of Sept. might have a spare relay.

 

Doh :doh:- Should have done this earlier - anyway a Google search for an 83 750 wiring diagram helpfully points towards information already on this forum!

Check out this link http://vfrworld.com/photos/showgallery.php?cat=500&ppuser=12957

Scroll down the images until you find the bundle of schematics. The second one seems to show item 8 as the fan Relay! I take it this is the item you have tested. But looking at the third schematic there is a reference to a cooling fan fuse! You should check that is not blown? The final diagram in the batch looks like the 83 VFR750 wiring diagram. Hopefully it is clear enough to allow you to track all the related current flows with a circuit tester. If all the circuits test out OK, then you need to check that the thermo-switch is operating properly as it seems to be responsible for controlling the cooling fan motors by providing an earth feed to what look like further relays located inside the motors.

Hope that helps



SkiMad

 

It is a 4 pin relay can't work any other way, it needs 2 powers to it, an earth and the 4th wire goes to the fans. To test the relayput one terminal on the neg of a battery, with a wire connect the oposite terminal to the battery positive, if you hear a click the relay coil is working, if not do the same test on the opposite 2 terminals. If neither combination gives a click then the relay is most probably faulty, The next test if you want to is after you have established which terminals give the click, you can set up a globe or meter across the other 2 terminals and once the relay clicks the light or meter should show a current flow. If not just get a 4 pin relay from an auto parts store

 

Hey All..I figured it out...To answer my own question and to hopefully help others...I followed my manual check list on tracing WHY my fans were not working..Grounded the thermostatic wires and nothing.Checked the 10a fuse that's operates both fans..I then straight wired both couplers that run my fans to my battery and both worked fine...SO,I traced the couplers bl\bu wire back to the "main relay" and made sure it was activating anything else..That told me the main relay was bad with out testing..SO,I straight wired the bl\bu wire to my bateery while my thermostatic wires were grounded and waaa laa..My question was...could I run a jumper wire from the red wire terminal to the bl\bu terminal and ot not mess anything else up...Answer is YES,I pushed a jumper wire in the female units red to bl\bu wire sections and then inserted the main relay..I then connected my positive side back to my battery. Neither the relay or the wires got hot and both fans cut on cause I still had my thermostatic wires grounded \ connected..The fans on my 83 vf750f are activated by the thermostatic relay..When the water gets a certain temp,it sends a ground to the fans and automatically cuts them on cause it suppose to have continuous positive voltage to the bl\bu wire....Best advice I can give is once you check fan operation at the thermostatic relay and that does not work..Next>check to make sure you have 12 volts at the 10a fuse..If you don't have voltage,its a bad relay or a broke bl\bu wire..If you do have voltage at the fuse,then check the fuse to make sure its not blown and then check the connections and voltage at the 2 fan couplers...If all that's good,then you have a bad thermostatic relay..

Thanks for all the advice and I hope my explanation was understandable..If not,PM me if your having the same problem and I will walk you thru it..
I was fortunate enough to have the original Honda shop manual with all the wiring schematics on 1 page..I seen on ebay where this manual is going for 200.00 so if I
can help anyone,I will gladly try..But be warned..I am no pro mechanic or electrician,lol
Allyance...Yes..if you have a spare main relay,i would like to buy it from you sir..Please PM me if and when you find out that you do..
Robert