2017 Limited Tacoma - repeated blower motor connector issues

Sometime last year my blower motor power started acting funky, come to find out the blower motor connector was burned up. I did some research here and found that this was not an uncommon issue for people. Some simple solutions that I learned from this forum which I have performed are the following:

1. Initially replaced the connector with a fresh OEM connector. This worked for a while until this new connector burned up again a few months later.
2. Then I replaced the blower motor and of course replaced the connector again. This worked for a while longer this time until now.... My blower motor connector has once again burned up.

I have read about people replacing the blower motor resistor. Seems like 90% of people solved this issue by replacing their blower motor resistor. I'm not so lucky because I have the automatic climate control system and there is no blower motor resistor down by the motor housing...

Someone suggested in a thread I found here that the wire gauge of the motor wire harness could be undersized, which could cause the connector to burn up due to resistance, however I haven't found anyone yet confirming that as a known issue.

I am the type of person that enjoys fixing things instead of paying someone else (and possibly getting ripped off!), but I'm also in unfamiliar territory here. Does anyone have any suggestions on next steps to diagnose this problem and help me get my A/C running again? It is summertime in Texas and I am sweating on my drive home today...

 

Which wire is melting? Power or ground I’m assuming.

You’re probably looking at a poor connection causing high resistance in the circuit (and thus high heat).

If you have an electrical schematic of this circuit, post it here.

 

@Dm93

 

How many miles you got on yours? I also have a 17 Limited 120k on it. No issues as of yet.

 

I vaguely remember a recall or tsb for the blower motor on models without auto climate controls.

 

The vast majority of the time when a connector terminal burns it's due to a poor connection most often caused by what's knows as terminal fretting, could be a poorly designed/manufactured terminal, poor pin fitment, or use of dielectric grease.

Products like DeOxIt and Stabilant 22A can improve electrical connections and help mitigate terminal fretting.

You said you used an OEM connector and I'm assuming motor but if you got them from Amazon/ebay and not a toyota dealer there's a high chance it's counterfeit/china junk.

The blower control module/resistor is typically the first thing to go when the blower is drawing too much current so I doubt it's that.

 

there was. The blower fan in my 2017 sr5 went out ….toyota fixed it for free.

 

There is a Special Service Campaign to replace the blower motor but it states it only applies to Manual HVAC systems.