BrianChevy

Dear Cooling Guru's please let me know what you think.
SITUATION:
CAR: 1987 IROC Z28, Dual Fans, 5.0 TPI
GOAL: Restore cooling fan control to ECM
PARTS: 4th gen Dual Fans and brand new TPIparts harness.

I bought one of these TPIparts.net harness. it sure looks like a quality part.



and i wanted to install it, but the plug (on the CAR SIDE) that it goes into has a wire cut just on the back side of it (it is just below my finger in the picture). it's the Black and Red wire that's cut. Does anybody know where this is supposed to go? Back into the front of Fusable link?




The other 2 pictures of interest are the backside of the fusable link (interesting eh?, also been cut and has a wirenut on it)-- pay no attention to the block, I installed that to try and find some solution to my other problems.





and the relay has a wire cut going into it as well. It's the big one that's black and red. The end has another wire nut on it and it's in my hand.


QUESTION:
So, i have 3 wires which are cut, need to know which goes where. Can anybody tell me?

<praying that my good karma comes back to me>

Thanks in advance. Looking forward to stock cooling with the 4th gen fans. I am going to be going in for a custom tune AFTER this, so I can program the fans to come on at whatever temperature we want, i know that the AC switch, pressure sensor, and 234 degree mark won't trigger 2nd fan,but I can pro-grammatically do it thru the ECM.


Brian

BrianChevy

is helping a little bit... i'm going to try and get this one resolved. any ideas?

Z28ricer

iTrader: (2)

Honestly I would ditch that "harness"

Go to the junkyard and retrieve some newer (90-92) relays and plugs, as well as the relay bracket above the C100 for the newer stuff.

Follow the 4th gens dual fan schematic, install a 160* thermostatic switch in place of the stock one to trigger the 4th gen "low", then use your programming and a/c output to trigger the high.

BrianChevy

I already have a 160* term and i'm happy with that one, i'm going back to stock-ish with 2 fans both controlled by ECM. the harness isn't THAT bad -- these are the only questions. I'm going to fix it, just need to know what to do.

abray1

Take that harness and plug it into a taurus fan (91-95 3.8l 2 speed) and you will then not have to worry about cooling your car off like I have for about the last 20 years. Dual fans, 4th gen fans, race fans, spal fans, etc. I have literally tried them all in all configurations and the taurus fan has almost cured cancer in my humble opinion. IT WORKS GREATTTT. The factory fans bearly work when new on a stock motor.

BrianChevy

Thanks but no thanks. I already have a new aluminum radiator, this is a full on build and i am certain that 4th gen fans will work for me. Appreciate the suggestions though. Just looking for a little electrical advice.

Z28ricer

iTrader: (2)

The taurus fan has been tested against the 4th gen fans, and flows a little above half what they do, it flows a lot more than most stuff, but doesnt quite keep up with them.

BrianChevy

I believe that 1 of my 3 connections goes direct to the battery and the other 2 go to each other. Any ideas or suggestions?

Brian

Z28ricer

iTrader: (2)

Sorry, dont have my book of thirdgen wiring here, its across town so it may be a day or two before I can give you the correct answer, and already tried to suggest you do it the correct way the way those fans are meant to be run, but it doesnt seem you want it done the right way, just good enough.

ZZ3 Z28

I wish I could you help you more but my car didn't come with dual fans and my shop manual lacks 411 in that category. But have you been to austinthird gen for help? I found these, maybe they are what you are looking for.

http://www.austinthirdgen.org/index.php?pid=2

http://www.austinthirdgen.org/index.php?pid=36

http://www.austinthirdgen.org/index.php?pid=23

BrianChevy

I think i have what I need to connect the 1 wire that needs to be re-connected. i will use the TPIparts.net harness that I bought and plug everything up with only 1 wire to repair. Thanks for the help.

BrianChevy

Ok. Updating this thread for my fellow ThirdGen.Org members who might come behind later looking for help.

I went to NAPA parts store and bought new fan relays (i got 2 of them), The part number i bought was a AR226, the list price is $14.49 (it also has a part number of V11306 on the box, i think that's the ACDelco cross reference number).

I hooked up both relays, built some trick water-proof protection for them and then ran the car at Idle. I occasionally rev'ed the engine a little, the temperature climbed, 180, 190, 200, 210, 220 and yet nothing.

I was starting to really get worried...

Then finally, right about where the gauge showed 230 -- the primary fan kicked on. I'm NOT sure that the secondary fan works, but I am sure that I can feed a ground to the Green wire and it will kick on. (i am going to run a line into the interior and be able to turn it on when ever i want by grounding it).

So, it appears that things are good with my cooling. <knock on wood>

Ozz1967

iTrader: (4)

That's a bit worrisome, simply because your primary fan should be controlled by the ECM and the secondary fan should be run by the fan switch. now, the fact that one fan comes on at 230 is good, that means the switch and relay are working.

articwhiteZ

iTrader: (56)

some of the Hot rod/ricky racer Guys, use a larger Relay. and set both fans to come on at the same time. on at 180/190 off at 160.

as there is No AC in the car's any more,..Why Not.
Works Fantastic. (been working for 20 years now)

Ozz1967

iTrader: (4)

That's what I'm going to do with my dual fan swap over, use the power from the single fan set up to energize a bigger relay that powers the new dual fan, tapping either the lead from the alternator or just strait from the battery to actually provide power to run it.

Ron U.S.M.C.

I'm no expert but it seems that all this talk about this and that can be resolved with a primary fan using a adjustable temp switch set at what ever temp. you want.(some thing to complement a 180* thermostat)Then use the second fan as back up when the temp. is reached (lets say 200* on, then 185* off) using a aftermarket switch in the stock location.I have a pusher/puller fan set up using a very similar design. It dose not hit the 220* mark. Very simple and effective system.

articwhiteZ

iTrader: (56)

I use a hyper tech Fan switch. 180. custom chip ecm, on 180/190.
larger relay to cover power to the fans..both come on at the same time. car never went over 200deg in the summer, with the stock rad. and the lingenfelter 383.

running the same set up, this 2nd time with the 427,
this time with a 3 core rad,

when the stock fans Kick in you can stand 30 feet from the back of the Car.. and it feels like a Hair dryer blowing across your legs..(on low)

this would be a sat night parking lot hang out with the car guys thing.
car would be not running..just sitting..then after about 5 to 10 min. as the temp was dropping the Fans would then turn off. (160 deg)

I love EFI

ninetyone

iTrader: (2)

ok,so u have a 160 thermostat,but did u get the ecm reprogrammed for this?are u using a hypertech thermomaster chip? are u even using an aftermarket fan switch which would turn on your secondary fan (passengers side) on at 176 degrees? That is the fan on temp when using a 160 degree thermo u know.

lizardkng

After my rebuild Ive only had the drivers side fan come on (havent driven the car yet), I replaced the thermostat with 180 instead of 190, so I need to get the ECM reprogrammed for that?

ninetyone

iTrader: (2)

Yes , you should get it reprogrammed for that. You actually replaced a stock 195 degree thermostat. Meaning thermo opens at 195 and driver's side fan comes on at 226 degrees and off at 220. That is stock. Now your gonna want fan on at 195 and off at 190. Otherwise all thats happening by adding a lower temp thermostat is the thermostat is opening sooner (at 180) but the fan still doesn't come on til 226 degrees. The passenger's side fan (secondary fan) should never have to come on. Only in extreme conditions like hot summer day with the air conditioner on High. Now, they do sell what is called a "fan Switch" which will turn that fan on at 200 and off at 185. That so called switch, is located between cylinders 6 and 8.