Removing FAN TSB causing battery drain ?
 

It's been a grueling two months of heat & humidity in Jacksonville, FL, and I've noticed that my radiator fans are staying on longer than normal (they do shut-off, not STUCK on), especially with the ambient temperature being so hot.

After a 15-minute commute, and a 1-mile cool-down into work, I pull into work at 9am, let the car-idle for about 2-minutes, and shut her off with a water temperature of about 195-F.

Since I have the factory Fan TSB (and the lower Miata thermoswitch), the radiator fans come on like they normally do.

At 6:30pm (elapsed time 9.5-hrs) I got and try and start the car and nothing.

I'm thinking the longer running times due to the higher ambient temps. is causing my 5-year old battery to drain down.

After being jumped and running her for 10-minutes, I go to Costco to get another battery (elapsed time 15-minutes) and she starts right up. Shut-off temp was 180-F, so no fans on when I shut down.

Any reason why I shouldn't just remove the FAN TSB module ?

Also, I don't think the big drain after shut-down is healthy for a starting-battery, so perhaps I should find a deep-cycle battery that fits ? If so, any recommendations ?

TIA,
:-) neil
1993 VR FD

IMHO, the fan recall is useless if you have good fan control. Keep the temps where they should be - as in, around thermostat opening temp (80-90 deg. C) and there's no need for the fan recall. That's just a hack to deal with the 107 deg. C stock fan switch and the pre-cat furnace under the hood. Mazda knew the cars were running way too hot and this is a band-aid to fix that problem.

I've been running without the fan recall junk for 2+ years now, using the HKS fan controller. No problems whatsoever. I went through my motor in March, coolant seals and passageways were just fine - this is with daily driving the FD like crazy, AC and Florida heat.

To remove the fan control, you have 2 parts - the ECU harness with the black box behind the ECU, and the short harness between the fan relays and front wiring harness. Should take a half hour tops to remove.

Dale

I removed the "black-box" behind the ECU, but not the short harness, since I don't know how it looks like.

Can you post a picture ?

Any harm if I leave the harness connected since it doesn't have the control-box ?

:-) neil