900 Electrical Problems

[iowapatriotfan]

It ran fine day one. Day two, brake light comes on, oil gauge starts blinking, and at end of day sled goes into limp mode. Won't go over 10 mph. Take it to the shop no codes on the earlier limp mode and limp mode now gone. They check brake lever and tail light harness which they say are okay. Tell me next step is to look at voltage regulator and they don't have time available.

Headlights went dim the next day when I pulled on the brake lever. Rented a sled. Loaded mine the next day and took it home. When I loaded it no gauges and not headlight, but it drove up on trailer with power.

I went searching for a bad wire.. Found wiring harness going to hood guages laying too close to underside of exhaust. Many wires were partially melted. I fixed them.. Headlights now work, but Brake light is still on, and now the High Temp indicator light is on too.. Digital temp readout is still working. Thoughts? I want to ride, need to fix and we have no dealers close.

 

[sw]

Wow! Anything else? A room full of guys who like to work on sleds would all run for the doors if they saw this sled coming at 'em! Who told you next step was to look at VR when a melted hood harness was staring at them! Seriously, I think you will need to pull up your favorite chair up to computer and go through all the 'stickys' at top of forum and then read everything else you can about the 900. Then download the deep snow manual on your computer for reference. I would concentrate on getting motor to run properly and 'code free' first, for now, don't worry about taillights/accessory electrical things, in fact, disconnect them at plug-ins. As you start to go through things you'll see the code chart among other things and see how some electrical is switched on through chassis ground and others are switched to ground through ECU. It's not what I would call fun, but it has to be done, that or be the first one out the door so as to not get stuck in the jambs with the three people behind you! Good workmanship is required on all repairs as the 900 will find the weak links in a hurry. Also don't be afraid to call up snowmobile salvage yards for parts that really don't matter if they're new or not. The hood harness comes to my mind as an example, electrical sensors I would buy new, search swap meet, Craigs List, etc. Good hunting!

 

[iowapatriotfan]

grounding via ECU and Chassis

Good info, I have spent much time on the various sites and did not notice the difference between the ECU ground and the chassis ground.. I will look harder at the manual and have already printed it out..

A dealer in Wyoming told me about the VR might be the problem..

I read inthe manual about the TPS, RPM, and Resistance of the temp indicator can make the high temp light come on? I tested the resistance on the temp indicator and it is a tad higher than what manual says, but it lowers as it gets hotter and rises as it gets cooler, so with the tester that I have is really old I say the temp indicator is fine.. I heard aout the TPS wiring being possible loose, so those are fixed now.

 

[sw]

Good work, you're well on your way to fixing this sled. I agree, I don't think temp sensor is bad, you've proven that. Because hood harness was melted, look at wiring diagrams on your manual, once you're on schematic, click on 'view' at the top of page and rotate clockwise then magnify. Look at gauge cluster and see the high temp light? Wire 27 (blu/w) starts at gauge 2 and leads to chassis/hood connection 1, then changes to 05 lt grn/r to gauge 1, then to 11 brn/w to brn/w splice which leads to air temp sensor & altimeter (if so equipped). Check these things for possible short to ground causing light to come on. In this way you should be able to get to the problems with sled, eventually the tail light issue can be addressed in this way. (the running lights and brake lights are different circuits) BTW years ago I had sore neck syndrome before a friend pointed out I'm an idiot and that I could actually rotate the view on those damm schematics! Also this is a good time to utilize the lights diagnostic port in front of steering post and above cyl. heads, MountainHorse has pictures in 'sticky' above and is shown in manual, chapter 13.44. Jumper wire 12V to port and you'll be able diagnose without engine running. Keep us posted!