Fan speed switch not working.

Thanks I aim to please you

 

You have a DC amp clamp? I wanted one back in the day, but man they were pricey.

 

I don't have one at home either. We do have them at work... At worst he can connect in series and get a reading if he has a meter that does DC Current.

 

$60 UNI-T UT210E Mini Digital Clamp Meter 100A AC DC Current Voltage True RMS Pliers Ammeter Resistance, Capacitance, Diode Tester Multimeter

https://www.amazon.com/dp/B0188WD1NE/ref=cm_sw_r_cp_apa_glt_fabc_12VSCJ939NJGR8YDW1Q6

But the diagram I made gave me exactly what I was looking for, a relationship between the speed settings with a DC motor load(exact dc motor settings don't matter) to help one understand why Toyota might have used a larger wire for the low speed on one year and M2 on another year. I can't help it's not worth anything for some people.

 

Yup, happened to me as well. Discolored the whits wire and melted into the connector. Ordered the Dorrman kit off Amazon. Got to be careful with the back screw as if you drop it, it goes behind the carpet. Works like a champ now.

 

If anyone needs it, I have the original connector. I was fairly certain that my resistor was bad, so I ordered the new one. In order to install the new one, I had to get the new harness. Installed the new stuff and everything worked for like 2 days. So the connector and resistor were not my problem.

I can get it to start back up if I apply pressure to the 4 pin connector that attaches to the blower motor, so I'm 99.9% certain that is where my issue lies.

All that to say, I have an undamaged resistor and grey inline harness (same style as pictured above).

 

There is no 4 pin connector going to the blower motor.

There is a 4 pin connector going to the Blower Resistor inserted into the duct for cooling. There is a 2 wire connector going to the blower motor.

Check them both for excessive heating.





This is what you need for the connector that plugs into the blower motor:

Part number

$13 for Compatible with Toyota Tacoma 2005-2016 Blower Motor Connector 90980-10916 6" 12ga Harness New

90980-10916 Connector

Part Number 82998-12380 Wire and terminal

Not sold as a kit, sold as each. So you will need one of the plugs and two of the terminal and wires.

Connector:




Terminals:

 

Well, I'll be....

I thought there were 4 wires going in there. I just checked and you are correct. The two pin connector going to the blower motor is the one that works when I put pressure on it.



I almost walked away before deciding to take the rest of your advice. Pulled it out to inspect and, well, think I found my problem.



So that leaves the question of what is the root cause? Can I replace the connector and it be fine, or is that just a temporary fix for a larger problem?

 

"Got to be careful with the back screw as if you drop it, it goes behind the carpet."
Ask my how I know!

 

I touched the connector and it clicked, then the fan came on normally on the low and medium settings. We'll see how long this lasts. This happened on my wife's 2006 Toyota PreRunner, I showed her where to touch the connector in case it happens again. No cost so far.

 

The reality of the issue regardless of whichever connector is burned/over heated is a loose connection between the male and female connection points. It boils down to this as a simple explanation:

A heating element in an electrical circuit is just a wire with a higher resistance. This resistance when current passes through it expends energy. This energy is converted into heat. This heat is what is burning the connection. The heating cycles hot, cold, hot, cold... causes the metal to weaken and the resistance increases, heat increases... until you end up with what you have now.

Some people think this is due to too much current, but that is untrue. An overall over current condition would heat the entire wire not just a local heating.

Replace the connector with new terminals and clean up the motor connector and you should be fine. Just make sure the terminals fit tight when pressed together.

 

If it clicked it wasn't pushed on completely.

 

I can’t speak for @Jimmyh.

But if you’ve already replaced the resistor and harness. Then all you have left is the connector on the blower. Unless the blower itself is going bad, and causing high resistance, there’s nothing else left to change but the connector. I doubt the blower motor is the root cause, but there is a “small” chance.

I’d inspect the plug in ON the blower motor. See the pin is black or melted?
If not, I’d replace just the connector. If it is melted of burnt looking, I’d be half tempted to change the blower mower. Bad connections create resistance, resistance creates heat.

 

Parts on order and are ready to pick up. Hope to have this resolved tomorrow.

 

Had a neighbor with wife and baby sweating in their truck stop by because they'd seen me working on mine so much. Told him it's a common problem and to wiggle the wires to get it to start, will get him by til he can get it fixed. No harm in a good while for a little bit while you wait on the parts.

 

Already been there and lost the screw.

A towel or t-shirt behind the resistor and the firewall, draped over the carpet gap will save the screw.

 

So, I have replaced the resistor, motor and new wires/plug. Plug was burnt at both the resistor and motor.

Still not working correctly, air on low and high thats its. None of the mediums work.

Could it be the switch? If so, how can I test that?

Did I screw up the wires?

 

Maybe. The only one that can answer that is you.

If you went with the new and improved resistor you need to wire it like this:

Old Harness -> -> New Harness
White/Blue Stripe -> (Hi) -> Solid White
White/Black Stripe -> (Lo) -> White/ Black Stripe
Green/Yellow Stripe -> (M1) -> Solid Green
Blue/Black Stripe -> (M2) -> Solid Blue

 

The Motor has 12 VDC at the connector all the time regardless of what speed it is running. The resistor works by changing the resistance of the ground leg.

The Short answer: Yes it could be the A/C Control Switch or the connector in the rear of it that may also have a burned connector. Pop it out and look at the connector first.

12 Volt Battery >> 50 amp heater fuse >> Heater Relay >> Blower Motor >> AC Control Assy >> Resistor >> Ground.

 

So what's the deal here, is this affecting the 2012-2015 models as well? I found the climate control unit on mine to be an issue some time ago as the plug was starting to burn ever so slightly but it was working fine so I tweaked the output pins to be from this - - - - to this / / / / (exaggerated) and replaced the control unit with one that did not have any burning on the full speed output pin. I haven't check it since but I assume the poor connection issue has been rectified back there.

As for the resistor and plug, are these affecting the later model 2nd gens as well?