Cooling Fan Qs please help..........!!!
I am ahead of beginner..but not an expert. So I have some not so easy questions

I have 93 maxima se which I love to drive. I found out that cooling fan run on 2 speeds low and high depending on temp.

But in my car it runs only high speed.

I have FSM it will run at low speed at 95C and at high speed 105C approximately (if car is below 20 miles/h speed or parked).

So I started looking at connections as per procedures (Fan running at low speed) in FSM. By speed I mean here running speed of the FAN.. and not the vehicle

So far it is OK with voltages and continuity at Fan Relay 1 and also at Cooling Fan. I also gave battery voltage to cooling fan pins directly from battery. it runs slow...

Now I can exclude
- connections from relay to fan motor
- motor
- Coolant temperature sensor (becos it can make fan run high speed if temp goes above 105c)


Now item left to check is Relay and connection from ECM to relay...

Can any one please help...
or any suggestions as to where I can get it fixed .. Dealer or any other automotive shop...

For the shop it should be that tough of a task.. since I have checked couple of things my self...

 

Here are my observations from my '96 GXE (RIP) and current '97 SE. Of the 2 fans, the driver side is the primary (fan 1) and passenger is secondary (fan 2). Fan 1 normally runs at a low speed when it's needed. When extra cooling is needed, fan 1 kicks on high and fan 2 starts. I have only observed it run at high speed. When the AC is switched on, both fans run at high speed regardless of engine temp. I also know from experience that if fan 2 goes bad, the car does not overheat, but the AC when stopped is very hot (really non-existent). This was for about a month straight in the summer in Louisiana (100+ weather). If I remember right, a fan 2 cost me about $120.00, and that's without the blade. And also, fan 1 has 4 blades, and fan 2 has 5 unevenly spaced blades. I don't know what that is for. Just a theory, but I think my fan 2 went out because that car didn't have the heat shield between it and the exhaust (the one attached to the fan housing). I didn't even know it was supposed to at the time. I'd guess 3rd Gens are probably similar.

Dave

 

The ECU reads the value of the coolant temp sensor and selects the fan speed. It's very possible that the program in your 93's ECU wasn't set up for a two speed fan. Nissan does things like that. Does your car overheat? Engine temp stay normal? If so, just leave it alone.