1998 LC. Heat/AC fan not working. Does not have Nav.

[BOB F]

I have the FSM for the 2002. It shows power into the blower relay on a white/red wire. If you are going to try to replace the control unit
I would look for part number 84010-60171. I just went through this process when I converted my navigation to a non-navigation system. These pieces are readily available for $50 plus shipping. Some places try to piece these out but most sell them like this.View attachment 1500753
View attachment 1500754 When you but them like this they come with the ac amplifier and the fan control. I could change this part out in 2 minutes. It pops off with a panel tool and plugs in with 4 plugs. They come either in wood grain or black as shown. I would check car-part.com for HVAC Heater/AC controller.

Wow. I'll look for one of those. That looks like the complete part in my 98.

Thank you

 

[TXSunDevil]

This is the troubleshooting recommended. This is a 2002 but it is the same as 98. You already know your blower works so I would focus on the Amplifier and relay troubleshooting.

 

[BOB F]

This is the troubleshooting recommended. This is a 2002 but it is the same as 98. You already know your blower works so I would focus on the Amplifier and relay troubleshooting.View attachment 1500767View attachment 1500769 View attachment 1500770

Hmmm. I don't get 1-3 v on that signal wire. I bought a used blower relay thing off an eBay parts guy. Wonder if that used unit is ng

 

[TXSunDevil]

Hmmm. I don't get 1-3 v on that signal wire. I bought a used blower relay thing off an eBay parts guy. Wonder if that used unit is ng

Make sure the switch is ON and you are able to get the tip of your meter in that tiny terminal block and is it a White and Red wire?

 

[BOB F]

Make sure the switch is ON and you are able to get the tip of your meter in that tiny terminal block and is it a White and Red wire?

Make sure the switch is ON and you are able to get the tip of your meter in that tiny terminal block and is it a White and Red wire?

 

[BOB F]

I need to check that voltage with it plugged into the resistor. I unplugged it and checked it. No good.

I have micro tips for the dvom to back probe. I'll report that. Probably tomorrow. Thank you very much for the help

 

[ITRJ]

So you have 13.2 volts on both large wires?
Have you check the voltage at the blower motor?

 

[BOB F]

So you have 13.2 volts on both large wires?
Have you check the voltage at the blower motor?

I did that at the beginning. Was getting less than 2,v.

I just went out and hard wired the motor to the 13.2 large wire input bypassing the resistor thing and the motor has a funny noise and isn't generating full power. Now I'm lost.

 

[ITRJ]

If you had the fan speed set to low, it's possible to get a low voltage reading at the blower motor. That's how the fan speed is varied. It should be close to battery voltage at the high fan speed setting. If the blower doesn't work when you jump power and ground to it directly, then replace it.

 

[BOB F]

If you had the fan speed set to low, it's possible to get a low voltage reading at the blower motor. That's how the fan speed is varied. It should be close to battery voltage at the high fan speed setting. If the blower doesn't work when you jump power and ground to it directly, then replace it.

I think I fried the motor. I put it back in and and rigged a hardwire to the harness thinking we could use it on high and off until I resolve the control issue. It wouldn't spin and the wires we're getting hot. I think it was binding dinehie. Reinstalled it and now it spins but with a noise and doesn't reach a usable speed. Ordered a replacement.

It appears to me that the full voltage goes to the blower relay on all settings except off and that the reduction in voltage for the lower settings comes from the blower relay with instructions to do so on that small signal wire.

The wsm you posted shows 1-3v on that small wire which I think is the variable signal with full voltage always on the large wires except in off.

Mine is only showing .4v in off and 0 in any other position which leads me to the main control unit. There is one full assembly on eBay for 325 right now. That's all I have found.

Does this all make sense?

 

[ITRJ]

before you replace the controller, check all your fuses. You mentioned some jumping to the blower and some hot wires. When you turn the blower to high, the relay should activate, sending 12v to the blower motor controller (terminal 1). The small signal wire should have 1-3v (terminal 3) and is the signal to vary fan speed as requested by the fan switch. You should also have around 12v at the wire from the blower motor controller to the blower motor. Also make sure you have a good ground (terminal 2).

 

[BOB F]

Update. I'm fixed.

It was the main climate control ecu on the knob panel. I got the whole panel off eBay for 300 something. Probably could have shopped that better.

The resistor I got off eBay is no good. It works with the original resistor. Got a blower off eBay to replace the one I killed.

The voltages off the main ecu told the story.

As an aside, I just buy a 2006 lx470 so this 1998 LC is for sale. 181k miles. Dark grey/almond int. Timing belt done at 172k. AC controls just fixed. New fuel lines and main brake line to rear just done. Runs great, no issues. Want to move it. $7995.

I'll post a complete ad soon. This is the first place I posted it.

Thank you all for the help with the blower issue.