Climate control fan speed same on 1-3

[Jason94sport]

I replaced the Blower motor resistor 2 times. Still the same problem. Speeds 1-3 are the same speed. 4 kicks on high.
Suggestions? It was working up until 4 months ago. No other problems.

 

[koda2000]

Maybe the fan switch is bad.

 

[J_C]

^ Agreed, the only thing I can see that would cause the lowest 3 speeds to be the same is if the fan speed switch isn't working so all 3 speeds are going through all 3 segments of the blower resistor pack.

You might try to spray some contact cleaner in, or brake cleaner, or whatever you have and work the switch around while it's still wet inside in case the problem is just hardened grease. I don't know if those switches can be non-destructively opened but if so you could open it and see if the contacts need oxidation removed. I mean it looks like they are held together with little plastic tabs and maybe you can get it apart or maybe the plastic cracks attempting to.

You could use a multimeter to check continuity of the switch contacts, but this won't necessarily tell you it's in good working order because it passes the fan current through it, so some contact resistance could effectively prevent proper speed control.

Regardless that switch is inexpensive, even the genuine Motorcraft is only $11 on Rock Auto.

2002 FORD EXPLORER SPORT 4.0L V6 Blower Switch | RockAuto

 

[3xowner]

I kinda have the same issue on my 2000.... so I am following.

is this a 2002 EATC unit?

Additional notes on mine... I've never replaced the resistor or switch... periodically when I hit a bump or something changes like accel the fan speeds act correct for a short time, then back to really no control to me on fan speed.

 

[3xowner]

Jason,

btw you posted this in 1995-2001 explorer forum... I really only checked this certain forum and perhaps others with 2002s only check that year range forum... may get more replies if posted in that forum... just saying

 

[J_C]

^ The Explorer Sport stayed with same 2nd gen Explorer design through 2003 (IIRC), so it would make sense to seek help in this forum.

 

[J_C]

I kinda have the same issue on my 2000.... so I am following.

is this a 2002 EATC unit?

Additional notes on mine... I've never replaced the resistor or switch... periodically when I hit a bump or something changes like accel the fan speeds act correct for a short time, then back to really no control to me on fan speed.

Those with EATC operate differently, have a transistor speed controller module where the manual resistor pack would be (on the firewall), and electronic head unit instead of manual rotary switch.

That yours (with EATC?) changes when you hit a bump, suggests either bad fan bearings or brushes (worn out fan) or some wiring harness short or connector intermittent contact. I could be wrong. Intermittent problems can be a PITA to find, otherwise I'd try to measure voltage at the motor connector (plugged into the fan, fan running, with a multimeter, to see if when the fan is going too slow, if there is a voltage drop there (meaning fan is not the problem unless it is shorted out - you could do resistance measurements on each winding but I don't know what the correct values would be, and shorted out internally would tend not to be something that comes and goes with bumps in the road, but I can't rule it out as impossible ).

There is some more info on EATC in this topic:
Automatic climate control problems

Sports were usually the economy model that didn't have EATC and other features that the EB's did.

 

[Jason94sport]

Thanks I ordered the fan switch. If I have to take it out to test or mess with, I'll just replace it.
I'll post the results.

Thanks

 

[Jason94sport]

Changed the switch no difference....Not a complete fail as I finally replaced the burnt out 194 bulbs in that cluster.
Any other suggests? Don't think I could have gotten 2 bad resistors?

 

[J_C]

I wonder if you have a frayed wire or connector fault. See the wiring diagram I attached to a prior post.

If pin 2 on the Blower Motor Switch isn't being connected to junction S257, through to pin #4 on the Heater A/C Control Assembly, that could cause this. Pull the plugs and look at the respective contacts in them, and use a multimeter to check for continuity or resistance from those respective contacts on the (might be Red/Orange, I'm uncertain on your '02 Sport) wire between the two.

I suppose it's also possible that the wire from pins 3 AND 4 on the blower motor switch aren't making it to the resistor, shown on the diagram as Lt Green/White pin 3, and Yellow/Red pin 4. Both of them would have to have a fault to not have one or the other intermediate speed working, and both can be checked for continuity or resistance as above. I suppose that's not impossible if some road debris or a mouse got up in the engine bay and tore them up.

As far as a bad blower motor resistor, it seems unlikely unless it has some severe design flaw or defect. As you can see in the wiring diagram, the Orange/Black wire contact to Light Green/White should measure some resistance, then Light Green/White to Yellow Red some more resistance, and again Yellow/Red to Red/Orange an additional resistance.

 

[koda2000]

If it's not the motor, resistor or fan switch the problem must be in the wiring or the connectors.

 

[Jason94sport]

It worked a few months ago. I didn't do anything, can't see how the wiring is suspect. Wouldn't it just not work at all? I don't have time or need to track it down...At least I have a low & high. Until that doesn't work I'll leave it alone.

Thanks

 

[J_C]

It wouldn't have to be you doing anything specific, things happen... animals, road debris, rain, sun, snow... well maybe not snow in South Fl, but possibly salty air there instead.

For it to not work at all, different parts of the circuit would have to fail rather the ones I mentioned specific to the switch and resistor connections.

Take the wiring diagram and a multimeter and find where the fault lies, or don't... I agree, you don't have to fix it and I too mostly use lowest or highest speed, but sometimes 2nd highest to make the cabin quieter.