2008 Toyota sienna righ fan alwasy running....


Asked by Sep 23, 2015 at 12:59 AM about the 2008 Toyota Sienna LE 8 Passenger

Question type: Maintenance & Repair

2008 Toyota sienna the right side fan runs as soon as key is in first position...I have full wiring diagrams and have replaced and switched around all the related the relays. I have replaced the fan control module twice (used), I have replaced the main ECU twice (both used ebay's but odds are they are not the problem). I know both fans work if hotwired so they are not the issue.  I have omed out related wires and circuits and chased back the wiring diagrams. I have tested the temp control unit and it works fine. I am stumped at this point. As a side note the AC is also not working and has a blinking light. I replaced the main AC relay with a new one, a known common problem on these cars. the AC gets cold if I "hotwire" the relay to always stay on but AC gauges shows rising pressure if i make it stay on all the time. AC gauges show normal expected pressures. First trying to figure out why just one fan runs all the time...second looking to solve the AC issues but not sure if they are related. Have been fixing cars for over 15 years and NEVER had to go to a shop for anything....just about there on this one....

1 Answer


Sorry a few other pieces of info about my post above....every once in a while the car can be totally cold, and the fan will kick on. I have an OBC scanner and the temp shows normal temps and goes up and down as expected. The relay that runs the fan, as well as several others have all been replaced or moved around to test. What else besides ECU, Fan Control Module, Temp sensor, or relays tells the fan to kick on....

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