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Fan fail light flickering/buzzing?
Posted: Tue Aug 05, 2025 10:49
by dancroft1984
Has anyone had this? Sometimes my fan failure light will flicker on, normally accompanied by some sort of buzzing/crackling noise.
I'm guessing it's probably something behind the dash shorting out, or is that normal? In the event of proper fan failure I'd guess the light would just stay on solidly.
As far as I know the fan is working perfectly well.
Re: Fan fail light flickering/buzzing?
Posted: Tue Aug 05, 2025 12:40
by Hawaiis0
I'd check the fan fail relay for water ingress or contact corrosion
Re: Fan fail light flickering/buzzing?
Posted: Tue Aug 05, 2025 12:43
by Marten
dancroft1984 wrote: Tue Aug 05, 2025 10:49
Has anyone had this? Sometimes my fan failure light will flicker on, normally accompanied by some sort of buzzing/crackling noise.
I'm guessing it's probably something behind the dash shorting out, or is that normal? In the event of proper fan failure I'd guess the light would just stay on solidly.
As far as I know the fan is working perfectly well.
The light goes on when there is a voltage difference between the command and the switched side of the relay. The relay is probably chattering away hence the buzzing sound. Check the relay, and that it gets proper power and has a good ground
Re: Fan fail light flickering/buzzing?
Posted: Tue Aug 05, 2025 14:07
by rbgosling
That light can be triggered by either fan not working when it should be on, or overheating, or low coolant. So any one of those could be the cause. If the cause is right on the margin that might cause flickering - and yes, the buzzing noise will likely be from the relay.
Re: Fan fail light flickering/buzzing?
Posted: Tue Aug 05, 2025 15:45
by Marten
rbgosling wrote: Tue Aug 05, 2025 14:07
That light can be triggered by either fan not working when it should be on, or overheating, or low coolant.
Maybe in later years? In the '85 wiring diagram the light is called fan fail light, and there is no temperature or level sensor in sight
Re: Fan fail light flickering/buzzing?
Posted: Fri Sep 26, 2025 22:15
by dancroft1984
Where is the relay located? I couldn't see it in the parts book. Mine is an early '85 car, so the pre-facelift interior.
Re: Fan fail light flickering/buzzing?
Posted: Sat Sep 27, 2025 08:47
by Lotus-e-Clan
Fan relay is in the driver's foot well under dash up on the right.
As well as water ingress, clutch fluid (takes on water) from the master cylinder dripping over the relay will cause relay damage. My fan relay was full of clutch fluid.
After replacing mine, I made a plastic tray to act as an umbrella over the relay assemblies.
See topic below for reference. The fan relay is towards the upper end in the photo next to the big yellow one (mine is an 89 se so you might not have a yellow one?).
Scroll up the topic to see the DIY plastic tray photo.
viewtopic.php?p=106454#p106454
Re: Fan fail light flickering/buzzing?
Posted: Tue Sep 30, 2025 10:27
by bash
My 86se doesn't have a fan fail at all.
Bash