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420A 97 Mitsubishi Eclipse RS HVAC electrical problems


Probationary Member
Mar 12, 2021
Bell, California
Hello, I have a 1997 Mitsubishi Eclipse RS. I am dealing with an electrical problem dealing with the A/C HVAC control. I was driving one day and my A/C went out.

Blower switch wasn’t turning on and the HVAC lights weren’t turning on. I took a look at the fuses in the interior. I saw that 10amp heater relay fuse was blown, so I replaced it with a new 10amp fuse.

When I put the car on the on position to test the HVAC system. The fuse was quickly blown. I did put a 25amp fuse on the 10amp heater relay and the A/C turned on the the green snow flake button on the HVAC system turned on. I know it’s only recommended to use the proper 10 amp instead of a higher amp.

What can I do to solve this problem?

I’m thinking it’s the heater relay or the blower motor fuse or relay. I recently replaced the blower switch on the HVAC system. I need suggestions on how to fix this problem.

At night, when I have my headlights on. The green light snowflake button is the only thing on. Usually it’s the emergency button and the blower switch button and the temperature button.

Please let me know if you have any suggestions on how to fix this problem. I don’t want to run a high amp fuse on the recommended 10amp fuse. Thank you !
Last edited by a moderator:


Probationary Member
Dec 5, 2020
Sacramento, California
When a fuse blows quickly it’s going to be a ground or open wire somewhere

Check all your ground straps, make sure that no wires or anything is cut open

RS, and base models have very limited features

We don’t have illuminated hvac like the GS and above


Supporting Member
Nov 25, 2002
Pearl River, Louisiana
Do not install a higher amp fuse.

Here’s what I would do:

Find the heater electrical schematic in the resources section of this website.

Unplug all of the components on that circuit, install a good 10a fuse, and see if it blows. If it does, you have a wiring issue. If not, Plug the components back in one by one (if there’s more than one) until you find the cause of the fault.
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