I have a Toyota Corolla 2003 1.8L (ZZE122) and the blower motor stopped working.

  • I checked the fuses - all good.
  • I took the blower motor out, hooked it up to an external power pack (16V) and it spins no problem.
  • I replaced the resistor with a new one.

Still no luck.

I get voltage on the blower connector, between 9V and 11V but even on full power I don't get 12V, so that could be a lead.

Any ideas on how to diagnose this issue further?

Thanks, Dom

2 Answers 2


So, after some more work I figured it out. I took the switch apart and there were no issues there. No burn marks or similar and continuity checked out.

In the end the culprit was the relay!

While it clicked fine, it didn't switch properly when there was actually power applied to the high current terminals. The deceiving thing was, I bench tested it by just applying 12V to the switching terminals and continuity switched fine on the other terminals, but once in the car, the switching wasn't proper (I had voltage across 87 and 87a).

Swapped it out for a aftermarket one, Toyota wanted >$100 AUD, the one from a specialised auto electric shop around here was $22 AUD.


  • Great news! Would you mind sharing the location/which relay controls the blower? Aug 26, 2023 at 7:31

That sure sounds like a broken blower speed selection switch. Remember that’s a whole lot of current running through that switch. Replace the switch on the control panel and you should be good.

I think its this one. Ouch. Expensive part at $170.

My guess is internal to that switch there is wear / burn marks between copper contacts.

  • Thanks @zipzit. Is there any way to check the switch with a multimeter? Oct 19, 2022 at 10:52
  • 1
    Nope. It’s a current capacity fail. I’m fairly certain that’s a wiper system switch. That is the contact hits a copper element. Yours is physically worn.
    – zipzit
    Oct 19, 2022 at 10:57
  • 1
    Before spending $!70 on what is almost certainly a non-returnable electrical part, I would carefully check the wires and connectors for damage. I agree is likely the switch but checking those other components first is a good idea.
    – jwh20
    Oct 19, 2022 at 13:26
  • 1
    If you have the switch taken out, you can test for continuity between the power in and power out connectors of the switch. Oct 19, 2022 at 13:33
  • In the end it was the relay Oct 31, 2022 at 1:32

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