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    Low voltage through ignition switch

    I have a problem with low voltage through my ignition switch. I get 12.5v+ from the battery, and if I connect my relay directly to the battery, it works great. When I check the voltage after it passes through the ignition switch (checking at the fuse box) I am getting ~10.5v, which is not enough to activate the relay. I spoke to bwringer about it, and he suggested running a can or two of WD-40 through the switch and rotating the switch to clean the contacts. After a large can of WD-40, and almost 1/2 a can of PB Blaster, there has been no improvement.
    Any other suggestions? Can the switch be disassembled to clean it?
    This is on my 83 GS1100E.
    Thanks.

    #2
    You should disassemble it. The switch is actually at the very bottom of the assembly and flooding it helps a bit it doesn't really get into the switch itself much. It should be like the one on my GS1000 and you can drop the whole switch out by removing the bolts up underneath it and then the plastic switch assembly is only held in with a small set screw. At this point I didn't completely disassemble the switch/contact assembly, I just flooded it with contact cleaner and rotated it until the cleaner came out clean. Some people disassemble the switch itself for a thorough cleaning but I already have enough little springs and widgets hiding all over my shop. When you rotate the switch pay attention to the orientation of the armature, it can be reassembled 180 degress out. I had the same drop in voltage you do and after cleaning the switch along with the kill switch and any other switches in the circuit like the clutch interlock (which I didn't have) I now only have a .5V drop at my coils.
    '84 GS750EF (Oct 2015 BOM) '79 GS1000N (June 2007 BOM) My Flickr site http://www.flickr.com/photos/soates50/

    Comment


      #3
      Originally posted by koolaid_kid View Post
      I have a problem with low voltage through my ignition switch. I get 12.5v+ from the battery, and if I connect my relay directly to the battery, it works great. When I check the voltage after it passes through the ignition switch (checking at the fuse box) I am getting ~10.5v, which is not enough to activate the relay. I spoke to bwringer about it, and he suggested running a can or two of WD-40 through the switch and rotating the switch to clean the contacts. After a large can of WD-40, and almost 1/2 a can of PB Blaster, there has been no improvement.
      Any other suggestions? Can the switch be disassembled to clean it?
      This is on my 83 GS1100E.
      Thanks.
      what relay are you using? Is it a 12V device?

      Comment


        #4
        Jim's right. 10 volts will activate a 12 volt relay.
        1983 GS 1100E w/ 1230 kit, .340 lift Web Cams, Ape heavy duty valve springs, 83 1100 head with 1.5mm oversized SS intake valves, 1150 crank, Vance and Hines 1150 SuperHub, Star Racing high volume oil pump gears, 36mm carebs Dynojet stage 3 jet kit, Posplayr's SSPB, Progressive rear shocks and fork springs, Dyna 2000, Dynatek green coils and Vance & Hines 4-1 exhaust.
        1985 GS1150ES stock with 85 Red E bodywork.

        Comment


          #5
          Originally posted by chef1366 View Post
          Jim's right. 10 volts will activate a 12 volt relay.
          Not sure who Jim is. It is a 12V Bosch-style relay I purchased off Fleabay. I have successfully used 3 of them on my car with no problems at all. It's not the relay itself because I have tried 2 of them with no luck.
          Perhaps I'll get one at Vatozone and try it, it is socketed so swapping it won't be a problem...
          Sandy, I didn't think about the kill switch and clutch interlock, yuch...

          This all started last year when I noticed my horn was weak, and testing revealed they were only getting 10.5V. So apparently it's been going on for a while.

          Comment


            #6
            Originally posted by koolaid_kid View Post
            Not sure who Jim is. It is a 12V Bosch-style relay I purchased off Fleabay. I have successfully used 3 of them on my car with no problems at all. It's not the relay itself because I have tried 2 of them with no luck.
            Perhaps I'll get one at Vatozone and try it, it is socketed so swapping it won't be a problem...
            Sandy, I didn't think about the kill switch and clutch interlock, yuch...

            This all started last year when I noticed my horn was weak, and testing revealed they were only getting 10.5V. So apparently it's been going on for a while.
            Hi I'm Jim

            Sounds like you should recheck the wiring to your relays. When the relay is activated you should see a solid +12V from the battery (if it is good). In otherwords there should be no drop at the output of the relay as compared to the battery +. This should be the case wether you have the circuit loaded or not.

            Comment


              #7
              Originally posted by posplayr View Post
              Hi I'm Jim

              Sounds like you should recheck the wiring to your relays. When the relay is activated you should see a solid +12V from the battery (if it is good). In otherwords there should be no drop at the output of the relay as compared to the battery +. This should be the case wether you have the circuit loaded or not.
              Hi Jim. I'm George.
              I have rechecked the wiring several times. All wired terminals (30, 85, 86, 87) are going where intended. The voltage from the battery is a solid +12.5V. The voltage from the switch is a solid 10.5V. I originally had the relay wired straight to the battery (no switch involved) and it worked just dandy.
              I admit to being a bit puzzled as to why the relay does not activate (perhaps because it is a cheap Fleabay product?).
              I am also concerned at the low voltage output of the switch, since it also powers my coils, lights, etc. I really don't want to dig into that circuit, but it sounds like I have two tasks: why my cheap relays don't like 10.5V, and why my switch is only sending 10.5V to everything that it powers.
              Oh, if only I'd bought that Bandit... (just kidding).

              Comment


                #8
                Just a few thoughts...is the negative lead of your voltmeter connected to a good, solid ground? Are you using the same ground for each measurement? Is the grounded side of the relay a good connection?

                If everything is not referenced to the same solid ground, the resulting measurements could be leading you down the primrose path......

                Finally, have you tried a test light instead of the voltmeter?

                Comment


                  #9
                  Originally posted by koolaid_kid View Post
                  Hi Jim. I'm George.
                  I have rechecked the wiring several times. All wired terminals (30, 85, 86, 87) are going where intended. The voltage from the battery is a solid +12.5V. The voltage from the switch is a solid 10.5V. I originally had the relay wired straight to the battery (no switch involved) and it worked just dandy.
                  I admit to being a bit puzzled as to why the relay does not activate (perhaps because it is a cheap Fleabay product?).
                  I am also concerned at the low voltage output of the switch, since it also powers my coils, lights, etc. I really don't want to dig into that circuit, but it sounds like I have two tasks: why my cheap relays don't like 10.5V, and why my switch is only sending 10.5V to everything that it powers.
                  Oh, if only I'd bought that Bandit... (just kidding).
                  All those Bosche Type relays are relatively inexpensive mechanical relays. That means when it is activated the only resistance is that of the relay contacts or the external connections.

                  I dont want to go through all possible combinations of how it might be possibe to miswire the relay, but the single check you could do to confirm if the wireing is wrong is to do the following:

                  You can not have a voltage drop between pins 30 and 87 when the relay is activated(well maybe if you have a direct short to ground but you would see smoke then).

                  So if if Pin 30 was the (+)battery and pin 87 was +10.5V then your battery has to be +10.5V and it is not fully charged (assuming normal ignition loads you should be closer to 12.0V with ignition on and engine not running; +12.6-12.8 with the key off).

                  So if you measure the voltage difference between pin 87 and the Battery (+) (which drives pin 30) and you see any voltage drop (when it is activated) you have the relay wired wrong.

                  So with the key OFF you might see +12V between pin 30 and 87; but with key ON it should drop to zero. If not it is miswired.

                  Comment


                    #10
                    I had a simillar problem with my 850. I did not do the coil mod, but I used a relay activated by the ign switch to feed power to the fuse block

                    Comment


                      #11
                      I recently found a related reason for the voltage drop. When pulling the small connector plug on the ignition switch, I noticed that one of the tiny male terminals was dark brown while the others were shiny brass. This was the main power feed from the battery.

                      I pushed out the terminal and it broke in my hands, partially corroded. It has a very weak spot at the locating tab in the brass.

                      Replaced with a spade terminal connector and all is well. Amazing that such a tiny terminal is used to carry all the current switched via the ignition switch.

                      Comment


                        #12
                        Originally posted by Matchless View Post
                        I recently found a related reason for the voltage drop. When pulling the small connector plug on the ignition switch, I noticed that one of the tiny male terminals was dark brown while the others were shiny brass. This was the main power feed from the battery.

                        I pushed out the terminal and it broke in my hands, partially corroded. It has a very weak spot at the locating tab in the brass.

                        Replaced with a spade terminal connector and all is well. Amazing that such a tiny terminal is used to carry all the current switched via the ignition switch.
                        It works while it works then it doesnt work

                        Comment


                          #13
                          Originally posted by SqDancerLynn1 View Post
                          I had a simillar problem with my 850. I did not do the coil mod, but I used a relay activated by the ign switch to feed power to the fuse block
                          That is really not a bad idea, but for the ignition/coils you still have to:
                          • get through the fuse box
                          • go to the right hand start button
                          • get back to the coils

                          So you have only taken the least part of the problem.

                          Comment


                            #14
                            Originally posted by posplayr View Post
                            It works while it works then it doesnt work

                            Jim, that sums it up nicely!

                            Comment


                              #15
                              Originally posted by posplayr View Post
                              That is really not a bad idea, but for the ignition/coils you still have to:
                              • get through the fuse box
                              • go to the right hand start button
                              • get back to the coils

                              So you have only taken the least part of the problem.
                              That is my goal. It is a 30A relay (40A off, 30A on, standard practice) so I want to be able to power lots of stuff when it starts working.
                              Since I have measured (who says "To know is to measure"?) that the voltage to all my devices is 10.5V, I want to remedy this. Since P=V*I, I know that nothing is getting the power it is designed to use. Or it is drawing more current than necessary, which is also a bad thing. Oh, why did I buy an old bike, surely an old car would not do this? Oh wait, yes it would, it would just cost more to repair...

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