2000 Limited EATC Issues

[1990_LX]

I have a 2000 Ljmited with the automatic climate control that has stopped working on me. No mater what I set the fan settings to the main blower motor will not come on when I want it to. It seems like a few months ago it would kick on intermittently and then one day half of the lights in the EATC control unit all stopped working at once. The rear blower motor works fine, it just seems to be the front that's the issue. I couldn't pull any codes out of it not have I found any vacuum leaks so I'm not sure where else to look. Any ideas?

 

[1990_LX]

Anyone before I start fires for the parts cannon at this thing?

 

[koda2000]

Are you sure the EATC is the issue? It could be the blower motor module, or the blower motor itself. If you're handy the module can sometimes be repaired. Next time the fan isn't on when it should be try tapping on it (from the engine compartment). If it comes on the motor is bad.

Rebuilt EATC - $100
New Module - $65/$80
New blower motor - $40

 

[1990_LX]

Are you sure the EATC is the issue? It could be the blower motor module, or the blower motor itself. If you're handy the module can sometimes be repaired. Next time the fan isn't on when it should be try tapping on it (from the engine compartment). If it comes on the motor is bad.

Rebuilt EATC - $100
New Module - $65/$80
New blower motor - $40

Nothing seems to jog it. I removed the resistor and it did seem corroded or bad unless it is common for them to fail in the molded portion on the plug and not on the coils like most I've dealt with. I just though it was odd that half of the illumination bulbs went out all at once and shortly after I started running into these issues. I will pull the fan and hook it directly to a 12V source to see if it spins to help narrow it down.

 

[J_C]

The blower motor transistor module on the firewall (aka resistor module, but with EATC your module doesn't have resistor coils, instead a transistor mounted on a heatsink) has three wires going to it.

One should read around 12V (from battery, with key in aux or engine on position), then when the dash unit is set to have the fan running there should be a base current flowing to the module on another pin, and approaching 12V output to the fan on the 3rd pin. I don't remember which order they're in but it may not be important to know as you're only dealing with 3.

If you don't have 12V input (no 12V or more on any pin) there's a wiring, fuse or relay problem. If you don't have base current there's a dash module problem.

If you have both 12V input and base current, and no output to the fan you have a transistor/resistor-module failure. If you have 12V input, base current, and up to 12V output to the fan but it's still not spinning then it's a fan problem.

If I were playing odds, without more info I'd say you had the dash module lights go out from a separate fault and now it's probably the firewall module that's blown.

 

[albi1cnobi1]

The blower motor transistor module on the firewall (aka resistor module, but with EATC your module doesn't have resistor coils, instead a transistor mounted on a heatsink) has three wires going to it.

One should read around 12V (from battery, with key in aux or engine on position), then when the dash unit is set to have the fan running there should be a base current flowing to the module on another pin, and approaching 12V output to the fan on the 3rd pin. I don't remember which order they're in but it may not be important to know as you're only dealing with 3.

If you don't have 12V input (no 12V or more on any pin) there's a wiring, fuse or relay problem. If you don't have base current there's a dash module problem.

If you have both 12V input and base current, and no output to the fan you have a transistor/resistor-module failure. If you have 12V input, base current, and up to 12V output to the fan but it's still not spinning then it's a fan problem.

If I were playing odds, without more info I'd say you had the dash module lights go out from a separate fault and now it's probably the firewall module that's blown.

X2. It's not uncommon for the controller module to fail over time. The motor draws a bit of current and it all flows through the control module. Like koda said, if you're handy you can take the module apart and re-solder it. The rear blower motor doesn't have a control module, it is controlled by the speed switch on the back of the console. You can test the motor like you said, by hooking it to a 12v source. If it starts, it's probably good.