What would cause the fusible link for the aux cooling fan to blow repeatedly?

I assume the motor is failing...it still runs, I assume it is drawing too much current and causing the fuse to go.

Per the scehmatic, there is only a single relay in the circuit- nothing that would cause the fuse to pop, though. Am I wrong?

Should I just replace the fan, or is more diagnostic work called for? (I have no easy way to measure 25+ Amps.)

A month ago it had blown, but I attributed it to a plastic bag wrapped around the fan. It is now to the point it blows every time I turn on the AC. I am guessing that the bag may have casued the motor to overheat to the point that the windings have melted/shorted and the winding resistance is much lower, hence the higher current draw.

Thoughts?

Thanks

Adam

Something similiar happened to mine. Not an easy job since the AC must be disassembled and rad and condenser removed to get to it.I replaced mine with an assembly from a 92 [2 speed fan plastic vs metal cage].Have the low speed connected as normal but put another relay to manually go to high with a switch [never needed it so far just in case I drive to Death Valley/Phoenix].

Fairly common for the fuse to blow as the motor wear out.

Sure makes a 5-6F difference in traffic both coolant and AC temp.

Q45tech wrote:Sure makes a 5-6F difference in traffic both coolant and AC temp.

With an ambient temp of 108 yesterday, it makes a *bit* more of a difference!

Thanks Dennis-

I'm just going to get the replacement motor from Joe T in scottsdale.

Question:

Do you actually need to open up the AC system??? or just loosen radiator and condensor to access? This will determine if I do it or I pay $180 to have someone else...

Thanks

Adam

Remove the rad, remove the condenser since it has hard rigid lines. Good time to air flush and examine all fins on both and use a straightner tool .While you are at it, new o rings where condenser connects.

I ran for 3 years without the fan working but I did little idling in traffic, that's probably why my compressor only lasted 10 years after the 1992 retrofit unit was installed. High head pressures.In late June new rebuilt compressor and new condenser, and new used 92 Fan and cage assembly. Still have 1990 evaporator.

Dennis-

Curious as to the difference in fan speed between the 'old' (90) single speed and the 92 two speed: is the high on the 92 equivalent to the single speed?? Or is the low?

I am guessing the high, since the pup already draws 20+ Amps (?), it would mean the 92 has a higher amperage fusible link, and that you'd need to wire a supply to add it in a 90. I'm guessing the 92 fan just gives you a speed between full and off.... your thoughts?

Also, just was passing penninsula infiniti in san mateo...stopped in to see if they had a fan lying about. (That I could buy for $240 instead of $150 from Joe T.) Not only didn't they have one, but the parts guy said "according to my computer, I've actually never sold one of them". I'm guessing that (a) in cooler climates the fan isn't used that much, so it lasts. and (b) in cooler climates even if it isn't working, nobody knows....

Thanks

Adam

My experience was close to Q45tech's. I ran for a period with no fan, but that was mostly highway and suburban. Then moved to Washingto DC, where driving, and I use the term loosely, involves sitting still in 97 degree heat. Needed a new fan, and also had to reroute the trans fluid out of the radiator straight through the B&M cooler to help keep the engine temp under control.In contrast, dealer here said it's common for fans to start drawing too much current as they age, and they had replaced many.

FWIW-

Fan motor is on backorder until 8/23... first time I've had to wait for an Infiniti part...

Also, the local Infiniti dealer and two Nissan dealers did not stock the 25A fusible links.

Feeling a bit under-served!:(

Thanks for the feedback-

Adam

All motors draw more current as they age: your fridge, your home ac, your vacuum cleaner.The reason your car's fuel pump fails, the transistorized variable speed control in the interior HVAC fails, the reason the window and sunroof motors fail.......age and hours of use.

Not keeping the ac system clean raises high pressure turning the condensor fan on, same with allowing the coolant to get above 195F out of radiator.

Replaced the motor for the Aux cooler fan.

No need to remove condensor!!!

(I had the susyem pumped down, leak tested, and a new reciever drier installed in Jan, so I wanted to avoid geting into the AC)

Removed the radiator (actually swung it up and out of the way- the Aux trans cooler was attached and I didn't want to remove the lines)

Loosened the receiver drier, the hose clamps on the AC line and the condenser mounts. Was able to pop it out JUST enough to get an arm in. Took apart the fan, (blades first, then motor) new motor, all back together, runs great.

Oil, filter and adjust drive belts while I was in there. 3 hours.

The world is a cooler place....

Adam

PS Should be 101F today in Sacramento....