hello i have a 2004.5 sportsman 500 ho that im having trouble with and was hoping someone here can help me out the hot and check engine light come on about 30 seconds after you turn key to on position ive checked over grounds replaced ecm twice with brand new polaris ecm replaced thermo switch ive done some continuity testing it also wont let me check the engine codes

 

Do the lights go off after engine cranks? If so I wouldn't worry about it. Left control switches were the main problem on not being able to toggle through diagnostics on speedos.

 

no thats the problem it constantly blinks hot and check engine and fan dosent work as for the diagnostic i can toggle thru the stuff with the left yellow button but i cant do the check engine light key on key off thing

 

Usually an ecm problem when this happens,but since you've replaced the ecm twice,problem could be in the speedo itslf.One other way is either disconnecting the battery or pulling the plug on the speedo harness.If that doesn't reset the speedo then still could be a problem in the ecm wiring/connectors,or the ecm or speedo itself. 2004.5 is basically an early 2005 Sportsman 500. Manual has a pin check on the speedo harness connector that can help you track it down along with good trouble shooting guides and wiring schematic.2005 Polaris Sportsman 500 Service Manual PDF Download

 

i have the manual and have gone thru some of the stuff i was pretty sure its not the cluster everything else on the bike works correctly i have a 5 volt reference at the thermo switch and all i can get at the fan is 7 volts

 

Then sounds like you need to trace wiring for shorts.First place I'd start is at the ecm connectors and wiring,then under the steering post where the main harness wraps and does all the pulling and stretching.I've had to strip the sheathing to find wiring problems like this if the ecm wiring and module aren't the problem. If you narrow it down to a faulty speedo,some have rebuild them rather than paying high dollar for a new one.Just a thought. http://forums.atvconnection.com/pola...ml#post3232409

 

do you think it could be the aftermarket temp switch one thing i did notice is if i unplug the switch and turn key on it starts blinking hot and check engine instantly if i plug it in it takes 30 to 40 seconds

 

I've read some posts about aftermarket sensors possibly causing problems but no definite answers. The hot light is supposed to come on when you pull the switch to the sensor with the key on. One way to trace it down is to use an expensive oem sensor,but that might not solve it. This is one area also that I'd check on the two sensor wires where they run up into the harness.All it takes is one bare wire to cause problems.

 

i did a continuity test on them it tested good but ill look to see if they are rubbed thru any where