Joe Cool Install

[David T]

So quick update. I jumped the a/c switch the other day and the fans came on independently just as advertised by this Joe Cool box (even filmed it to prove they were both spinning). Figured it was good and took the car out and my temp gauge almost hit 220 with no fans. Before they would turn on well below that mark so I shut off the engine to let it cool down as I was scared to overheat my newly acquired Delorean!

Question now is how can I test the otterstat to make sure it still works? I find it hard to believe that it magically broke at the same time I plugged this box in! I tried searching the site but wasn't able to find any specific steps other than jumping the otterstat. Thanks again!

You put the switch in a pot of water with a thermometer and hook a continuity meter to the switch. You heat the water and observe the temperature at which the switch closes. You may also have to check the temperature of the temp gauge in the dash. It could be inaccurate. Best way is with a non-contact infra red temp meter.

[Bitsyncmaster]

So quick update. I jumped the a/c switch the other day and the fans came on independently just as advertised by this Joe Cool box (even filmed it to prove they were both spinning). Figured it was good and took the car out and my temp gauge almost hit 220 with no fans. Before they would turn on well below that mark so I shut off the engine to let it cool down as I was scared to overheat my newly acquired Delorean!

Question now is how can I test the otterstat to make sure it still works? I find it hard to believe that it magically broke at the same time I plugged this box in! I tried searching the site but wasn't able to find any specific steps other than jumping the otterstat. Thanks again!

If the fans came on with the AC and not the otterstat, you probaly have a bad connection on the diode. There are two diodes in the harness on the right side of the relay compartment. Or it could be you just got a failure of the otterstat at the same time. Jumper the otterstat to prove the diode and wiring are good.

[eight8toy]

You put the switch in a pot of water with a thermometer and hook a continuity meter to the switch. You heat the water and observe the temperature at which the switch closes. You may also have to check the temperature of the temp gauge in the dash. It could be inaccurate. Best way is with a non-contact infra red temp meter.

Thanks for the reply. That sounds like a lot of work haha so I just ordered a new otterstat switch since they are pretty cheap. Doubt mine was ever replaced before. If that doesn't solve the problem then I think the trash can is the next place I'll install this old Joe Cool unit! Probably just need to get in touch with Dave regarding his nice relays or go back to my original setup. Just didn't like how whenever the fans came on the "cooling fan fail" light came on, seemed odd.

[Christian Dietrich]

Not alot of work at all. First, just the otterstat wires, if they fire up, then you have a bad otterstat, if not, then check the diodes. Start with the simple stuff first. It ain't hard 😆

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[Bitsyncmaster]

Thanks for the reply. That sounds like a lot of work haha so I just ordered a new otterstat switch since they are pretty cheap. Doubt mine was ever replaced before. If that doesn't solve the problem then I think the trash can is the next place I'll install this old Joe Cool unit! Probably just need to get in touch with Dave regarding his nice relays or go back to my original setup. Just didn't like how whenever the fans came on the "cooling fan fail" light came on, seemed odd.

There would be very little difference to the Joe Cool unit weather the AC or otterstat is requesting the fans to turn on. What the DeLorean does is feed the AC signal into a diode and feed the otterstat signal into another diode. Then the other side of those diodes are connected and that signal drives the fan relay (now your Joe Cool).

I was going to suggest buying a new otterstat (don't cost much) but you came to the same conclusion. It still may be wiring which is a common problem with our old cars. The otterstat wires get the signal inside via the bulkhead connectors. Now the Joe Cool unit probably has less load on that signal than the fan relay does. Normally that would make the Joe Cool work work better with marginal connections.

[DavidProehl]

Just didn't like how whenever the fans came on the "cooling fan fail" light came on, seemed odd.

Just in case you didn't realize it, this was probably an intentional wiring change a previous owner did. Some owners like a visual indicator that the fans are on because they don't trust that they will turn on (not really an issue with Dave's relays). I can't seem to find a link to the wiring changes, but if that is all you are trying to change a new otterstat probably won't change that. You may need to reverse some minor custom wiring to bring it back to stock functionality.

[eight8toy]

Ok just to update this topic I replaced the otterstat today (lost about a cup of coolant trying to be quick) and cleaned up the wiring harness a bit with a wire brush. Zip tied the thing too. Got the temp up and just as advertised one fan started and then the second one kicked on a second later. Seems very coincidental that the day I installed the Joe Cool my otterstat died but just glad it works again!

And the "cooling fan fail" light doesn't illuminate like it did before so I'm very happy. Thanks again for everyone's help with this!

[Joe Kuchan]

Ok just to update this topic I replaced the otterstat today (lost about a cup of coolant trying to be quick) and cleaned up the wiring harness a bit with a wire brush. Zip tied the thing too. Got the temp up and just as advertised one fan started and then the second one kicked on a second later. Seems very coincidental that the day I installed the Joe Cool my otterstat died but just glad it works again!

And the "cooling fan fail" light doesn't illuminate like it did before so I'm very happy. Thanks again for everyone's help with this!

A Joe Cool will INTENTIONALLY light the fan fail light if one or both of it's internal 15 amp fuses has blown so that you know that you've lost one or both fans. That's it way of saying there is a failure. You need to open it up and replace one or both fuses.

[Christian Dietrich]

A Joe Cool will INTENTIONALLY light the fan fail light if one or both of it's internal 15 amp fuses has blown so that you know that you've lost one or both fans. That's it way of saying there is a failure. You need to open it up and replace one or both fuses.

Not necessarily. My fan fail lights always worked with the original factory set-up. My Joe Cool unit failed but not a blown fuse, a shorted out solenoid that engages the fans and DIDN'T trigger the fan fail light. So when i restored the car's interior, i got with Dave McKeen and bought his solid state fan fail relay and solid state fan module along with his led hvac board. So now i know when the fans are on and if one fails. Best safety update i did with 11035!
Since the lighting is blue, the fan logo lights up green! You have to have all 3 pieces for this to work. Like i said, its a wonderful safety feature and piece of mind.

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