weird and bizzar electrical problems are often the power splices. wish i could tell you exacly but you will need to go through the loom and check 'em. but start under the fuse block. they corrode and open and things can backfeed. weird stuff. another poster here has his engine cranking when he turns on the key.

this was a TSB a few years ago.

 

Thanks Mongoose, I guess I'll tear ir down and see. Any specific spots I should look at?

 

Check relays?
Check brake light switch, If it's the same type configuration as on later models, it could be messin with you too.

And as always, battery cables TIGHT! Connectors greased?

and WELCOME to the site, not_nick

 

Thanks, I checked the starter relay and it seems ok but weird thing is for a little while I could hold the brake and turn the key on and wait about 5 seconds and let it go and it wouldnt start, then I walk to the back of the bike and tap the starter relay and it started up. Is it in the relay then? Where can I get a cheap replacement relay to see if that is the problem?

 

Hi, I have a 04/ 400 and I went and had a look to see if this might help, somewhere there is a wire problem for you, do not know where but here are a few things you can try, download the service manual for your 04, it should be on this site, and start with the wire diagrams, my starter relay has the large wire from the battery to one side of the relay and a large red wire from the relay to the starter + 2 small wires, I would disconnect the 2 small wires connected to the starter relay and then carfully remove the red wire to the starter from relay at the relay, now there should be power to the relay from the battery so take your voltmeter and check that there is 12 + volts from wire connected to relay to ground, and make sure your ground to frame is clean and tight, this is important. Now if you take the red wire that goes to the starter and touch it to the wire from the battery it will spark and should turn over the starter motor which if your key is on and bike is choked should start the quad, if this works then you know that the starter should not be your problem and can look at the relay and thoses 2 small wirers as a place to trace back the electrical with the wire diagram. Next put your voltmeter on the starter relay to the terminal that goes to the starter, there should be no volts, if there is then there is a problem with the relay, those 2 small wires with voltmeter check them and see if there is voltage, the yellow with red line should be from the starter button that would pull the starter relay coil in to connect the 2 big wires and start the quad and then drop the relay out when you take your thumb off the starter button, this wire should only show 12 volts when button pushed, no other time, not sure about the other wire,it is white with red line, it is the return to ground through all the safety features, check diagram, there are other built in features to starting the quad like shifter placement, ie, park or in gear and if in gear then push foot brake to start in gear all have some input to the white wire with red stripe from relay so lots to check but you have to know what wires to the start relay do what and where they go, if the relay is good then it has to be ground or the 2 small wires, hope this is clear enough and helps

 

Check your ground. Everywhere there is a grounding strap in the harness, make sure it is clean and grounded. I have chased similar gremlins on other makes and have found that the grounds were bad. Once, I couldn't find the issue, and making up a new ground wire solved it.

 

thanks guys, i will try all of those suggestions as soon as i can, I really think its got to be a bad ground some here of something bc i had the whole quad apart and couldnt find frayed or smashed wires. I also believe the relay is working correctly but the small wire from the starter circuit is getting power when it shouldnt be and i cant figure that out

 

hi, I went to check the electrical on my quad, the 2 small wires, the yellow with red line comes from the starter button and shows no volts till key turned on and button pushed, then 12 + volts,and it shows 12 + volts when gear shift selector is in any position and button pushed. Now the other small wire, White with red line is the return to ground but first all the criteria of the safe features must be met, so either in park or in gear with fooot brake pushed but should show no voltage through this wire and no ground so not sure how this works, it may all meet up in the speedo head, you said that the ground shows ground, white wire/red line at solenoid, it should not show ground, that is why it tries to start, so there is a problem there and so do not start it and run it till this fixed as it is keeping the starter engaged unless when it starts it drops it out, voltage to the red starter cable at solenoid would tell when running, try to disconect your speedo head and see if you loose your ground with white wire or need to figure out where this wire goes, there needs to be a small brain that keeps all the input info for safe start like a ecu on the newer machines, the blowing of the vr may have taken out more than just what you replaced and you are sure the speedo head is for that year of quad. hope this gives you something to work with, as a last ditch try you could make a plug that would go to where the white wire goes and then to ground, this will let you start and ride but with no safety feature and there may be other problems that you might want to know about with speedo head dead, does the oil light work, and shift indicator, 4 wheel indicator, and when running check voltage to battery and make sure it is not over charging, I guess you could always pull start it, just disconnect the white wire first, mine starts second pull

 

I figured there had to be some type of control module to control all those safety features and other things. On the speedo, the gear lights works, the oil lights work and i think the 4x4 light but i will have to check on that. It is still ridable as long as soon as it is started, it is shifted into gear and the starter cuts off. Do you think I may have gotten a bad speedo head? Also what is the box infront of the handle bars underneath the plastics? It is labeled Denso and has a part number. When i Disconnected it the quad wont start so I guess its some type of ignition control. I doubt that has anything to do with it. And the small wire that delivers the +12v to the relay is hot when it is not supposed to be. I need to see if we still have the old speedo and see if that will fix the problem. Thanks so much for all your help!

 

I found a wiring diagram for your unit and could send it to you, I need you to clarify, you said the wire that delivers the +12 v is hot, can you tell me which colour wire is this, is it the yellow/ red line or the white/ red line and whichever it is what reading do you get from the other of these 2 wires and the reading with the key off and on. Take the wire, white/ red line off of the starter solenoid and this will prevent the starter from engaging when you are checking with key turned on, From the wire diagram the speedo head is just lights and speed dial and odometer plus some small stuff but not related to your start problem, there are some 1 way diodes that may have some connection if they have shorted out. ​

Electronic Module
​

​

When other components have been tested above
and are good, the electronic module can be suspected.
Ensure wiring and connectors are in good​

condition prior to replacing the electronic module

Removal
The electronic module is located under service
compartment. Remove the front fender.
To remove, unscrew both bolts retaining electronic​

module to frame and unplug the connector

SPEEDOMETER
Using a multimeter, measure the voltage between
both RED/VIOLET and BLACK wires.
Turn ignition switch to ON. The obtained value
should be between 12 and 14.5 Vdc.​

–

No voltage on speedometer:

​

​

• ​

​

Check wiring condition and electronic module

connector. If good, change electronic module.
​

​

– ​

​

Voltage on speedometer:

​

​

• ​

​

If VSS (Vehicle Speed Sensor) voltage is good,

change speedometer.
​

​

• ​

​

No voltage on VSS. Check VSS and wiring condition
from VSS to electronic module MPEM

If solenoid test good, check the electric starter. If
starter test good, the electronic module can be​

suspected.


​

​

​

​

​

​

​

​

​

 

The yellow/red wire has 12v as soon at the key is turned on. the other small wire has no voltage and it is grounding properly. I do suspect the electronic module. Where can I get a replacement from?

 

Hold on, as I stated in my other post and now that you have confirmed, I trust you are using a voltmeter, the yellow/ red wire should not have any voltage in it when the key is turned on, this is the wire that comes from your starter button on the left side handle bar, you will need to take the switch off and check out as to why there is power getting through this button, the wire you are looking for are Red/ violet line, which is main power in to switch from key so this wire should show no voltage when key is off and 12+ when key is on, the other wire is the Yellow/red which goes from button to starter solenoid and this should show no volts at button and 12+ when button is pressed.
This needs to be delt with first,

there are a few switches that will need to be checked but first thing first,

hold off on looking for the electronic module as from the wire diagram it controls power to the ignition coil which then gives spark to plug and it also controls the override for going backwards and the kill switch.

 

Another thing you could check is lights that turn on in the speedo head, when I turn my key on the speed indicator is driven backwards and rattles and all the lights in the speedo head come on then everything settles down to just the oil light on and shift indicator, so for you does the park light turn on when shifter in park, and reverse light and neutrel light.

Also, does you tail light work when key is on and does brake light work when foot pedal or hand lever activated, this may cause a problem if light does not work properly.

So I went out and did a check on mine to get an understanding of how this all works, the wire diagram only helps understand,

You will need to move the shift indicator for this test through all positions, as there may be just 1 position which would be a switch that is faulty, just a matter of isolating where the problem is,
Key on,
The white wire/ red strip with it unplugged, from starter solenoid
(1) there should be no voltage showing from plug to ground,

Turn key Off

(2) there should be no reading when set voltmeter to ohms from plug to ground,

(3)diode check, set your voltmeter to diode check, this is indicated by an arrow point into a flat line, red + wire from your voltmeter to plug, black - wire to ground
have shifter in these positions

P= diode reading should be about 512 and then squeeze hand brake and it should drop to 511,
R= 533, squeeze, should drop to 531
N= 512 511
H=534 531
L= same as above

OK if you do not have a diode test on your voltmeter this will be the final test,
you will need a small 12 volt test light like a small amp bulb and socket or bulb and wire from a dash light or low wattage/ brightness bulb, not a brake light or headlight, so now take the wire from bulb and push it into white wire redstrip plug, the other part of the bulb or wire you want to touch to the + terminal on the starter solenoid, which is the one from the battery, you are trying to put power down the white wire, through the diode to ground and bulb should light up in all shift selector positions, we are trying to represent the pull in coil on the starter solenoid with the low watt bulb and it gives a visual when bulb lights and we do not want to burn out a diode by using a high watt bulb, there are 3 diodes in the wire harness. This test is the route the 12+ volts takes when you push on the starter button.

Somewhere something is going to show up, it could be a diode or a switch, there is not much more and it could be just a poor ground at the switch that indicates your shift position.

 

Just to finish up here, your speedo head has a speed sensor with 3 wires attached and they go into the transmission area, the wire colours are Red with brown strip, pink and black with orange strip, there should be a plug with these wire colours and also these wires go to the plug to the speedo head so you could check that the wires are good from head plug to speed sensor plug

 

I'm still betting on a bad ground.

 

Yes you could be right for sure, just a matter of finding that point as there are a few ground points and he did have the voltage regulator go which seems to have taken out the speedo head and headlights so the owner said

 

I am assuming that when a diode is burnt out it will allow power to flow backwards, if not then this does not apply. If 1 of the diodes is burnt/ shorted out, with the key on you could get a 12+ reading at the white wire/ red stripe at starter solenoid and also your brake light could power 12 volts to plug if diode was burnt/ shorted out with key on. With key on and position selector in H or L if you shorted the white wire plug to ground the brake light would light or the light in the speedo head would light.

 

Okay, I do not have the quad here now, it will be back tomorrow, but I did do a few things you listed already. I ran current through a test light using the white and red wire from the relay as a ground and it did work. I also pulled the switch apart and it is only getting power to it when the key is on and it is connecting the circuit when pressed. As far as doing the diode test with voltmeter, I have not done that and I will have to check to see if the voltmeter has that function. I can see where a bad diode could cause it to back flow but that still wouldnt allow it to start. The red and yellow wire has 12v when ever the key is turned on and the brake is not applied and when the shifter is in park or neutral. If the brake is applied the brake lights light up like normal and it cuts the power to the relay. Also if it is in H, L or R there is no power to the relay. I will do some further tests when i get the quad back. Also, My speedo does the same as you described when the key is turned on. Thanks again for all the help

 

Hi, so I a bit puzzled with the info I have from the wire diagram and what you are telling me, so have to ask again but just need some clairification on a few things, wire colour from the starter button, from what I can see with the diagram there should be 2 wires at the button, 1 Red/ violet strip which is power from key and 1 Yellow/ red strip from button down to starter solenoid, this wire goes no where else but from the front handlebar to the back solenoid,

(1) are the colours right or is there another colour at the button?

so if the wire colour is correct then if you disconnect the yellow wire at the solenoid and then put your voltmeter red lead to this plug and black lead to negative or ground of frame is it
(2) 0 volts with key off and
(3)0 volts with key on and
(4)12+ volts with button pushed?

 

You are right about the bad diode would not put power to the solenoid and make it start, it was just that there should be no voltage at this wire or ohms reading, the white wire should show like it is disconnected because of the diodes, key off or on, if it showed something then there might be a problem but it still would not make it start, the diodes are a 1 way only pass through, they allow the voltage that is coming from the starter button to pass through the coil in the starter solenoid and then through the diode and then throught the P or N switch to ground, When in gear, R or H or L, when brake is applied the power goes through the brake switch to ground.

 

You did not say if the tail light works when the key is turned on, that bulb has 2 filiments?

The bulb is on and bright with the key on and real bright when brake applied?

You say, The red and yellow wire has 12v when ever the key is turned on, do you mean the yellow wire with red stripe?? I am sure you do. Where are you getting this 12 volt reading from, the back at solenoid with the wire disconnected and your using the frame as ground?

I am trying to look at the wire diagram and see how you can get 12 volts to this wire when key is turned on but 0 volts when key off and then when brake switch activated 0 volts

So when you say, If the brake is applied the brake lights light up like normal and it cuts the power to the relay, do you mean and have you tested by removing the yellow wire which I would take to be the one from the starter button that there is power to the plug and then when brake applied no power to the yellow wire plug and

do you have more than 1 brake light?
Is it the original rectangular tail/ brake assembly?
I only have 1 brake light in the center back. I guess I am interested in where you take your voltage readings from and that you are using the frame or the negative on battery as your ground. Once I know about the wire colour from the starter button and where this 12 volts is being read from and then how the brake switch effectes the 12 volt reading,

Also if it is in H, L or R there is no power to the relay. this is how it should be and I take it that when you push the starter button when in any of these selections it will not start and yet when you apply the brake it starts and brake light works, this also is how it should be.
So it is with the P and N that there is some glitch.

There is no custom wire job on this machine that is not from the factory? Some one added a wire for something??

Hope this helps and sorry about my need for detail, just trying to add what you say to the wire diagram.

 

How long has this problem been going on, since the voltage regulator went or when the second speedo head stopped working, or before any of this or after the last speedo reading??

 

it is 12v+ as soon as the power is on. The button doesnt do anything. It is so weird

 

You will have to take the multi switch off with the start button, there must be a plug in for the multi switch some where along the wire harnes, It could be that the button is either stuck on or else the contacts have become fused closed, you may be able to take the button apart and see if you can fix the problem or else if this is where the problem is and it can not be fixed your options are to try and get another multifunction switch, new or used or disconect the wires at the button, the red wire from the key and the yellow to the solenoid and buy a water proof switch that springs back to position when you let go and attach the 2 wires to it and mount it somewhere that works, hopefully you can unplug this harness and do a test on the switch with it out of the machine. You could also test the yellow wire at the plug at the front point that goes to the starter solenoid and see if you are getting voltage there, it should read 0 volts, if it reads anything else you will need to find where, somewhere in the harness from the solenoid at the back to the plug point up front