Fan delay relay operation

[Turbo6Smackdown]

Ok, can anyone explain the fan delay relay operation to me? At what temps did this thing look for before it went into operation? How long did it stay on for? And do TT chips shut this feature off? I put a new one in a few years ago but never seen my fans come on after I've shut the car off. I actually think it's a great idea. Anyone?

 

[RmvBfrFlght]

My understanding is that, if at key-off the fan was running on high speed, it will continue to run via the delay relay. For how long I don't know. The high speed fan running isn't controlled by the ECM, so can't disable it in the chip. High speed is via the temperature switch on the intake manifold or via the high pressure switch on the A/C system.

And of course the delay relay. Which many remove as they are known to just 'turn on' and drain the battery.

RemoveBeforeFlight

 

[Pronto]

Unplug the damn thing and forget it.

 

[Turbo6Smackdown]

I want my fans to cool it though lol. The shit works man

 

[Pronto]

It's useless. Worse than that if it fails it will kill your battery. You won't know until you go to start it unless your with your car for hours. Nothing like getting stranded by some idiot failed relay.

 

[turbo nasty]

disconnect it...

 

[Pronto]

Can't get more insight than that!

 

[Turbo6Smackdown]

That's yours - mine's brand new... I don't have that problem. I just want it to work how it was supposed to from the factory

 

[TurboWh1]

10 minutes is the delay time. Can wire high speed to run and then shut off automatically. Works awesome assuming you have a good relay

 

[GNVenom]

http://www.installationinstructions.com/FYI/delay-relay.pdf

Explains it all. It has no practical use except to be a source of major electrical problems when, not if, it fails.

Remove it and call it a day.

 

[Frederickdav]

I replaced mine this spring, thanks Dennis, but, instead of just replacing the relay, I added the angled metal "cover" that Kirban also sells. The object is to keep water from entering the relays. I prefer having the fan run for a few minutes to having all that heat sing raise engine temp way up. I should do a comparison like how hot it gets with and without the delay.

 

[GNVenom]

You won't see much, if at all. The delay relay runs the fan across the radiator ONLY, not the cooling system since the water pump is not running. A cooler radiator has little effect on a hot engine with coolant sitting still. You need to pass coolant thru an engine, then thru a radiator to reduce the stored combustion heat.

 

[mikestertwo]

It actually does cool the engine down through convection. It works on my Cadillac also. I hooked up a manual switch to run the fans when the engine is shut down and it dramatically drops the temperature of the engine. Back in the old days...I'm dating myself...there were tractors that didn't even have a water pump and yet they ran cool. As long as the thermostat is open the water will circulate though very slowly.

 

[Pronto]

One of the sites top electronics expert is telling us it's a waste. What more do you need?

 

[TurboWh1]

http://www.installationinstructions.com/FYI/delay-relay.pdf

Explains it all. It has no practical use except to be a source of major electrical problems when, not if, it fails.

Remove it and call it a day.

Great article! I learned something new today. Never had an issue before but it sounds like its not worth the risk of leaving it in. So it sounds like the fan will function as normal with no delay relay?

 

[TURBOPOWERED68]

remove the relay hit with very big hammer, put in fire pit, bury it in an unmarked grave and NEVER EVER TALK ABOUT IT AGAIN.

 

[turbo nasty]

You can lead a horse to water but..........

 

[GNVenom]

Fan will function just fine without it.

It's the usual "prevention not worth the cure" case here. Eventually you *will* develop a problem with that part.

This is 80's technology, produced just before the time the automakers embraced the all-sealed-connections method of preventing eventual moisture-related failures. Look at current automotive technology; every wire and connector is 100% sealed.

Not so with our Buicks.

And don't even start me on the firewall bulkheads and fan-fuel-AC relays....

 

[Coelacanth]

I read through all this info a couple years ago when I started restoring my car, and got rid of mine toute suite. Taped up the connector and the engine bay looks just a tad less messy, which is all good.

I actually remember a couple times when my dad still owned the car that the fan came on for no reason during the night and killed the battery. That's enough of a downside to not bother to consider any upside (and there's no upside).

 

[RmvBfrFlght]

There is another upside to removing the delay relay (can also use the powermaster feed if it has been swapped out). Run the large red wire to the alternator S terminal. Will need a plug that has that wire in it (junkyard).

Once this is done the alternator will 'sense' the voltage at the starter terminal. This causes the vehicle voltage to increase as it makes up for the voltage drop between the alternator power terminal and the starter terminal.

RemoveBeforeFlight