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Fuse Box Multi-meter test?

8K views 20 replies 2 participants last post by  dpapavas 
#1 · (Edited)
Battery Melted, Bad Rect/Reg, Fuel Pump Not Priming...FIXED!

Hi everyone!

06 GSXR 750, My battery melted on me due to a bad reg/rect and since then has been replaced. The battery acid leaked onto half of the fuse box, the side with the high and low beams and ignition fuses. I have replaced all of the fuses which restored power to the dash, horn and turn signals. The high, low beam and the fuel pump wont turn on. Can't get into dealer mode either. Is it possible to test the fusebox to ensure they are closing the loop? If so, how would I do this?

Thanks!
 
#4 ·
One other question. Would it be possible to follow both cables and probe the end of each connector rather than at the fusebox?
By "both cables", I assume you mean the wires at each side of the fuse. If so, the sure you could do that, but the more stuff between the probed points, the more chance there could be a broken connection sowhere other than a the fuse box. Given the condition of the fuse box though, that's rather unlikely.

Another quick test, would be to test the voltage at the fuse. If it's not battery voltage, then there's a broken connection between the battery and the fuse, presumably where the wire coming from the battery is entering the fuse box.
 
#7 · (Edited)
You have been a very big help! Pretty new at checking things with a multi-meter but love learning so this has been actually quite enjoyable other than the fact of not being able to ride.

I am making progress just trying to understand what I am seeing at this point. I found out, thanks to your help, that the ignition fuse keeps blowing when kill switch is set to run. I am still checking voltage and continuity in my spare time. Tested the high and low beam and they are getting 12 volts so no short there. Unplugged the fuel pump relay and fuse blew, unplugged the fuel pump and fuse blew too. Still have some continuity and voltage testing but I think I have narrowed it down. When I unplug the black connector on the ECM the fuse stops blowing so I think its a short in one of those cables or ECM short. I bought the bike used and it looks like some of the cables have been spliced and replaced so I need to check those too.

I am a bit confused on some voltages I am seeing. Is it normal to see 12 volts across all power cables or do some get reduced to like 5 volts?

Thanks Again!
 
#9 ·
SIDE-STAND RELAY INSPECTION
First check the insulation between D and E terminals with the
tester. Then apply 12 V to terminals D and C (+ to D and - to
C) and check the continuity between D and E. If there is no
continuity, replace the turn signal/side-stand relay with a new
one.

http://www.suzukigsxr.cz/docs/Suzuki_GSX-R_750_K6+K7.pdf page 436

What does it mean by "First check the insulation between D and E terminals with the
tester"? A resistance or continuity test to make sure there is no connection?

Thank you!!
 
#10 ·
What does it mean by "First check the insulation between D and E terminals with the
tester"? A resistance or continuity test to make sure there is no connection?
Yes. This relay is "normally open" meaning that, when not energized, it should be an open switch. To verify that, set the DMM to the highest resistance measurement scale (unless it's auto-ranging) and measure between D and E. You should still get an out of range measurement, meaning the resistance is practically infinite. Consult the manual of your DMM to find out how it displays out of range measurements.
 
#13 · (Edited)
Thank you!! I have been confused about voltage testing a bit and this is helping! I hope you never have a leaked battery or burnt ECU either **knock on wood**

I am seeing really low voltage coming out of the starter relay. .34 or so volts on the Y/G and B/Y wires. I am guessing that is not normal and possibly my short. I should be getting 12 volts here, correct?

Picture of where I am getting low voltage below.

image ru
 
#15 · (Edited)
No. The ignition fuse blows if I put the kill switch to run which may have nothing to do with this test. I will check though. Thanks!

Update: I did check at the ECU and not getting any voltage when pressing the start button or pulling clutch switch with kill switch set to kill and run. The ECU was unplugged during this test which prevents the ignition fuse from blowing, the black connector on the ECU specifically. I thought I was getting same voltage at ECU but was incorrect after retesting. I remember now that I tested continuity between these cables and it was good, low resistance. The place I was getting low voltage was on the left and right hand assemblies at the connections marked when the ECU is connected only. Disconnecting ECU to test there I get no voltage. Maybe I am doing it wrong? Everything I am reading is pointing to a short to ground in the ECU. Wires all look good and only low voltages come from cables going through the ECU. All other power cables giving 12v or 5v and the cables look good, no burnt cables. I ordered a working ECU and hopefully will be here by Friday. Please wish me luck and keep your fingers crossed that it's just the ECU. Once I get the bike running I'm going to test the stator to make sure it didn't go out when the r/r melted the battery.

I really want to thank you again dpapavas! I have a lot of learning to do and you have helped me soo much through this. I am really enjoying the community on this site!
 
#16 ·
It does sound like it's the ECU. Are you getting battery voltage at the O/G wire at the dealer mode switch, when the ECU is disconnected and the engine stop switch is set to "RUN"? Also, have you checked the wiring (at least a visual inspection) of the fuel pump relay, fuel pump, EXCVA and STVA? When the ECU comes online, it cycles/primes all these devices so faulty wiring on any of them, that are somehow powered through the ignition fuse, could be blowing it.
 
#17 · (Edited)
I have a O/W wire on the dealer mode switch that I am guessing that is the same as O/G. It looks like that wire goes to the kill switch which I have checked for voltage up until that point which was getting 12 volts. I will test all points on this cable after the kill switch just to be sure. I nearly took the wiring harness out of the bike but tested without having to do so, just moved things around to get a better look. Nothing looks burnt or damaged on the EXCVA or STVA. Checked the connectors too like disconnected and visibly looked for damage inside them. Cabling looks really good. There was a slight black mark on the ground coming out of the starter relay and I have checked that to make sure the ground was good, that is the only thing I have found that looks burnt. I was hoping to find a short in the harness because that would have been less $$$ than a replacement ECU but not finding anything. Will report back in about 5 hours for voltage at dealer mode switch and other points. Thank you!!!

Update: I am getting 12 volts out of the dealer mode switch with ECU unplugged and kill switch to run. Also getting 12 volts out of cooling fan relay, fuel pump relay, and the O/W wire that goes to the ECU connector. Didn't check the ignition coils yet but will tomorrow, I'm exhausted tonight :(
 
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