I need assistance please. The light on the Hvac controls was blinking. Lost a/c. Did the research. I replaced the magnetic clutch relay. As well as getting the Freon filled. It still is blinking. I tried 4 different ones, since they come in two packs. Figured if they were faulty. Even swapped it with the fog light one. Anyone have ideas of what the issue might be?
Blinking a/c help needed
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Syr4RinNC
New member
First thing is the relay in the fuse box. TRy to jump it or replace it to see if the relay has failed.
There is a diagnostic mode you can check with the HVAC controls on the interior
My problem ended up being that the HVAC control module/ (sometimes called an AC amplifier went bad)
AC Amplifier replacement 4th gen 4runner
There is a diagnostic mode you can check with the HVAC controls on the interior
My problem ended up being that the HVAC control module/ (sometimes called an AC amplifier went bad)
AC Amplifier replacement 4th gen 4runner
Thank you for giving help. How do I learn about the diagnostic mode? How did you end of figuring it was your hvac/control module?
I ordered the mag relay, the updated grey one. Perhaps the ones I ordered were the original ones that were faulty. How do I jump it in e meantime to see if this was the issue?
Thank you so much. The links came up broken. But I was able to research. The code just flashed 00. Assuming it’s not reading a fault?
Ironically your link was broken too. Maybe it’s Tapatalk. Are you talking about the sensor in the dash that gets dirty? I just went to clean it.
I had this problem intermittently in the past. I did change the hvac panel control module last year due to a switch not working. But this issue was evident for the previous panel as well as this one.
For anyone who needs it, the PDFs for the DTC diagnostic mode and the AC DTC code chart are in the following linked topic.
Here is the instructions for entering A/C diagnostic mode.
Here is the instructions for entering A/C diagnostic mode.
Syr4RinNC
New member
Did you replace the actual panel with the buttons
Toyota 4Runner Limited 2003-2005 AC Heater Climate Control Clock Display Panel 55900-35430 Used OEM - July 2022 - 247carspares.com
or this
Toyota HVAC Control Module Air Conditioner 88650-06350 OEM Free Shipping US | eBay
Oddly it works intermittent. Like this morning. Then I shut off and then back on. Then it doesn’t work. Now I just checked and did the diagnostic again, which showed the 00 code. But it’s working again. I’m wondering if I need the updated relay. The grey one. Which I have in order.
One thing that can cause this is the revolution sensor in the compressor. If it doesn't send a signal saying that the compressor is turning the computer thinks it's locked up. In order to prevent the belt from being burned off it will turn off the compressor and signal the lamp to blink. I don't know if that's what you've got but it is a possibility.
MikeinNH67
Senior Member
When I had this issue it was that relay sticking in the on position. There's multiple relays in that box that are the same model. Try switching the A/C one with one rarely used and see if that helps.
Mine used to do it and I would shut it off then turn back on and it would correct it. But now it won’t correct it turning it back on
This is great info. Can I replace the sensor without replacing the compressor? Can I do it myself? Possible to test it?