va454ss

Must be missing something obvious. Using pin C2 on the EBL and the recommended relay. Have tried to relays. WUD shows fan is being called for, but am getting nothing.

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90 454SS; TBI 496. Best to date: 12.42 @107, 1.63 60 ft.

92 454SS; stock with Wynjammer.

RBob

The ECM output pin will go low when the fan is commanded on. This is with the stock cal where the "Option Word 3 - Bit 0 - FanHi" flag is un-set (off).

The relay coil is to be wired from +12 volts (switched) and then the other relay pin to pin C2 of the ECM. A simple test is to key-on, engine-off and ground the ECM pin. That should activate the relay and turn on the fan.

You can ground the quad-driver outputs without issue. Just do not tie one to +12 volts.

These relays also have an anti-kickback diode across the coil. So it is important that the coil pins are connected properly (in regards to +12V and the ECM driver).

It is also possible that the quad driver is bad. With the WUD showing the fan on measure the voltage at ECM pin C2. It should be lower then 0.7 volts.

RBob.

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www.DynamicEFI.com

'92 Camaro in Dark Green Gray Metallic

va454ss

Got it figured out.

I had the option bit set.

The diagram shows no ground going to the relay. Would the ground go to "C"?

RBob

No need for a ground. Terminal C on the relay is left open.

http://www.dynamicefi.com/EBL_Drawings.php

RBob.

va454ss

OK. Just wanted to verify.

Pre-Tuner

I'll be installing a set of dual fans from a 2K Camaro into my truck and I have a few quick questions.

Where do you get the actual terminals from for the ECM connector? There's just an empty slot there now, right?

Would I wire both fans to separate relays?

I don't know if these fans have a high and low speed yet since I won't have them for a few days. It sounds like the EBL will only control one speed, so should that be the low speed?

Thanks

RBob

There may or may not be an emtpy slot at that position. It all depends upon the harness used for the install. For a pin/wire I just get one from a current connector. At yards on a vehicle where the engine was cut out the ECM harness connectors with about a foot of wire can be had cheaply.

The reason is that a cut out engine also means the harness was cut. So they are happy to get even a few bucks for the connectors and short wires.

For dual fans, there are several ways to go. Whether there is a need for two relays depends upon a couple of items. First is the current draw of the fans. If one relay can handle it, then can run both fans from the one relay.

Note that I don't recommend driving more then one relay from the ECM. So if two relays are required can have the ECM controlled relay kick on the other relay. This way both fans run together with just the one relay controlled from the ECM.

Another method is to run one fan from the ECM. Then run the other fan from a head temperature switch. Which switch to use will depend upon the thermostat used. Usually have the ECM kick on at a lower temperature. Then if the temp keeps rising have the head switch kick on the other fan.

Or, if these are two speed fans, run the low from the ECM, and have the head switch run the high speed.

RBob.