Car Overheating - Cooling fans not working

[Monster]

Help, My cooling fans arn't spinning. I was hoping someone may see something that I missed. I did some test in steps. (My car is far from stock as I drive a Monster)

Step 1 - checked fuse by drivers leg - Looked good.


Step 2 – I jumped the 4 cables from the two fans (2 blue and 2 black ending in Spade Connectors) straight to the battery. Only one fan worked, the passenger side. I have 1 known issue at this point, but this still points to something electrical overall.

Step 3 – Skipped the heat sensor test because with the AC unit on it should bypass and starts both fans.

Step 4- Replaced Relays and Fuses (ordered 1)




So far still nothing.

My plan is to install the cooling fan relay when it arrives, (next Thursday) and if that doesn’t fix it I am pretty much at a loss. I don’t know what else to test. I think my cooling system consist mainly of Miata parts so next thought is turn to Track Dog Racing for help??

I see 2 things to fix.
1. Whatever is keeping the fans from coming on
2. The driver’s side fan (unless my bypass test would only activate 1 fan (that doesn’t sound right))

Can you think of anything else I missed? I feel like I covered the bases pretty well.

Thanks for any help or ideas.

[POS Racing]

Step 2 – I jumped the 4 cables from the two fans (2 blue and 2 black ending in Spade Connectors) straight to the battery. Only one fan worked, the passenger side. I have 1 known issue at this point, but this still points to something electrical overall.
.

So do you get voltage to the dead fan??

[wizzurp]

I can't remember how a stock miata is set up but most cars are controlled via a temp sensor on the motor, if that fails it may not register to the fans that it is ever getting warm. Other vehicles are ecu regulated but that seems to be less common on older cars. Maybe check your temp senders?

[Monster]

POS, I believe so. I wired it directly to the battery. I think I have 2 problems, a dead fan, and an electrical problem getting the power to them in the normal way.

Temp sender is bypassed for the AC. They should both lick on when the AC is activated regardless of temp.

I have ordered a new relay that should arrive tomorrow. Hopefully that will cover the electrical side of the problem.

[POS Racing]

Good stuff here on how to test a relay:

[Monster]

New relay came in today and that was it. Problem solved. The fan was my own issue. When I was testing it I let it scrape the housing. Grrr. I created a lot of extra work but learned a good lesson. Thanks for the tips, and nice video.

[channelmaniac]

You may want to get a relay with beefier contacts.