So I thought I got a pretty good deal for a 2007 G35s sedan. Test drove great besides a exhaust leak at the cat, worn brakes, and ac needs a recharge.

First day of going through the car went well did the engine oil, diff fluid, and checked transmission dipstick and fluid was great. Drove it around, car felt great besides a little hesitation in rpm when rpm drops to 1.5k going to a full stop. Going to clean the throttle body and maf and possibly spark plugs.

Now the main issue I would like some guidance on. I recharged the refrigerant and to my pleasure the AC compressor kicked on....YES....all these years of driving built cars as commuters I finally have AC. I allowed the car idle with AC on full for about 15 mins and didn't notice anything weird so decided to drive it to my buddies shop. When I was waiting at a light and looked down at the temp gauge and to my dismay the needle was pointed 2 bars under H!!!! At this point I was already entering the freeway so I had to keep driving to which then the temp bar dropped back to normal so I completed my commute....drove it again today to work and this is what I noticed.

-driving with ac OFF needle stays just under the halfway point. After 10 mins of driving it then hovers around the middle of the gauge and starts creeping up to 80% mark at a full stop. When I begin to drive needle drops back down to the 50% then work up to 80% at full stop. A constant cycle. Turning the heater at full blast brings the temp back down to normal
-driving with ac on first ten minutes of driving car temps are normal then after 10 mins it starts creeping up to 90% temp at full stop. When driving consistently the needle hovers around 60%

**no coolant leaks
**resovouir tank coolant level fine
**Driver side fan works strong but stays on all the time
**passenger side fan- stays on regardless if ac is on or not but seems weak I can put my finger while running and it won't hurt. A lot weaker than driver side fan, are both ps and day fans supposed to have the same strength?

Ordered a new thermostat and going to flush and bleed the system and try to clean the radiator and condenser with a power washer on Thursday, is there anything else I should look at?

Thanks guys!

 

The fan motors are probably shot. They are known to go bad on these cars. Mine went bad after 11 years a few months ago and paid about a 100 bucks for a new unit. Took about an hour to swap in my driveway.

There are some relay and wiring tests you can probably do to be sure, but it's most likely the motors.

 

That's what I was thinking but I have never worked on g35s before.

Does your ps and ds fan pull air with the same strength or is one side weaker than the other? Also does your fans both stay on while car is on or only one fan.

Thanks

 

They run at low speed if one relay is turned on and they are supposed to run at high speed when the ecu turns all three relays on I think( I forget). Both fans should be on high speed when the ac is on at op temp or higher I believe. You can look up the exavt specs in the fsm.

 

All 3 relays are located at the IPDM (behind the battery fuse box).

The 4 pin connector at each fan can be tested with a digital multimeter, low speed you should have battery voltage across 2 pins, high speed will have battery voltage across the other two pins as well.

 

Okay going to test those out tonight thank you. So the ipdm for my 07-08 sedan is located next to the battery like the fsm says and not in the footwell in the driver side cockpit? Been reading a bunch of threads and some say footwell behind the fuse box. So just wanted to make sure. I really appreciate the help

Also came across these relays.


Correct relays?



From another thread for an 07-08 fan relay issue

 

That's the AC blower fan relay in the pic (blue relay), it's mounted on the backside of the cabin fuse panel. Not the ones we're talking about.

Definitely troubleshoot the problem before ordering any parts it's EXTREMELY common for the fan motors themselves to go out on these vehicles. Maybe everything is working fine and your thermostat died, that's another common issue, troubleshoot!

 

Got it thank you, definitely appreciate it. I'll report back my findings

 

Tested the fans with a known working fan module off my buddies car. Fans now seem to kick on and act normally however the passenger side/ac fan is still very weak compared the the driver side fan regardless of how hot the car gets. Haven't had a chance to test with a multimeter yet but seems like a bad fan motor.

Have a new fan assembly with module on the way and going to flush coolant with a new thermostat this weekend.

I do want to check the relays as well but had trouble located them physically and on the fsm.


I am assuming it is different from older g35 models?




Found a radiator amp fuse

 

Not sure in the 07, but on my 06 they are right next to each other. Make sure you get that cover back on real good also. Water has a habit kf getting there amd shorting out the IPDM

 

Alright, dug into this a little bit more and it appears your 2007 sedan has a single relay and a control module that sends variable output voltage to control fan speed, not the more basic mechanically driven system that my 2006 has with the 3 relays. I would wait to replace the control system of your vehicle until you've replaced the thermostat and verified the problem still exists, I STRONGLY suspect it's just a failed thermostat. If you have access to a digital infrared thermometer (kind with the little laser you point at something to see the temperature) shoot the radiator hose for the intake/output sides of the radiator to make sure it's cooling off, should be about ~200 F going in and ~150 F coming out of the radiator. If you need more exact numbers I can go IR scan mine.

Starts on page 67, page 68 has the location of all components including the relay.

http://www.nicoclub.com/service-manu...7_G35_Sedan/ec

 

OP,

Did you ever solve this?

If you replaced the cooling fans/motors, did that fix the problem?

PLEASE let me know,

Thank you!