My wierd rad fan situation (Page 1/2)
D43DLU5 JUN 10, 10:34 PM
https://imgur.com/a/FCOfrMp (photos of what my current wiring looks like.)




My 1984 Fiero SE with a/c had a fan installed by the previous owner replacing the stock 2 speed with a single speed. The image link above shows how the fan is wired.

Fans hot is wired to the neighboring harness, black wire is grounded to the rad frame, you can see a small part of the ceramic part left but it's pretty much all gone. One wire on the harness is left disconnected.

I have replaced the temp switch on the side of the engine facing the front of the car with Rodney Dickmans low temp switch and wired it to the green/white wire. This has made no difference to fan performance when the engine climbs the scary part of the temp gauge.

Now the fan DOES work when the a/c is turned on, regardless if the compressor is running or not. My compressor caught tire (yes, tire...) on the highway and is currently inop and disconnected.

Bottom line, car will stay cool in motion and when the a/c switch is turned on. Turning it on with the a/c switch causes massive power struggle and nearly stalls the car if I am not moving. Is my fan wired correctly in the pictures? Is there a better way to wire the fan without messing with the relay? Should I consider redoing the whole wiring setup for the fan?

Edited to upload pics directly to post.

[This message has been edited by D43DLU5 (edited 06-11-2020).]

Patrick JUN 10, 10:40 PM
I was just going to suggest that you upload your images directly into your opening post (or use the Image link to where they're currently stored). Makes it easier for people to see what you're referring to.

[This message has been edited by Patrick (edited 06-11-2020).]

fierosound JUN 10, 11:52 PM
Here's the wiring diagram for the 84.

------------------
My World of Wheels Winners (Click on links below)

3.4L Supercharged 87 GT and Super Duty 4 Indy #163

theogre JUN 11, 12:26 AM
Both from the relay should be splice to + wire for single speed fan.
Or can replace the resistor to have two speeds again.
CLICK FOR FULL SIZE


Your car Should Already Have/had a lower temp switch on engine. Was No Point buying RD part.

I see No "ceramic part left," only hacked wiring job by a fool.
Unless you think crap splice on ground means something... Sorry just more hacking.

At minimum you need to cut out all crap splice to fan motor.
Replace w/ better weather/water resistant splices and if crimped done w/ proper tool not crap crimpers from Kmart and most auto part stores.
Should have enough wires so only 1 splice needed for + wires plus 1 new loop end for ground.

ETA-->In the Short term cut out red wires and tie 3 ends w/ a wire nut. If plan to leave it that way, stuff the nut w/ silicon or brake grease. But watch you don't over torque and nut fail now or later of mechanical overload.

If you still have problem... Likely have other mods or fan control parts are bad.
Very likely you have other big problems in the coolant system causing the car to "over heat."
Car can run 200 to 220°F easy but even at 235°F is normal in slow or stopped traffic.

See my Cave, Rad Fan, Thermostat and rest of section.
Get Stant SuperStant too.
See my Cave, Wire Service too.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

[This message has been edited by theogre (edited 06-11-2020).]

D43DLU5 JUN 13, 06:07 PM
I've fixed up the wiring and have both of the wires from the harness tied together to the yellow positive wire from the fan. Turning the A/C on will still switch on the fan but the fan will not turn on even when the temp on the car reaches the red.

The fan is good so the issue isnt the fan itself. I know the switch is good because it is brand new. I suppose all that's left is the relay and the wiring from the engine bay to the relay. Are there any other obvious points of interests I could look at or am I looking at replacing all wiring for the cooling system?

I should add that the car stays cool in motion, when the a/c is turned on and will only overheat if traveling at low speeds or in traffic. I want the fan to be able to turn on without having to always switch on the a/c.

[This message has been edited by D43DLU5 (edited 06-13-2020).]

Gall757 JUN 13, 06:21 PM
The temp gauge is not accurate. Let the car get a little hotter and I bet the fan will go.
Patrick JUN 13, 06:27 PM

quote
Originally posted by D43DLU5:

I know the switch is good because it is brand new.



That roar you hear in the distance is everyone laughing. New parts (especially in this day and age) are often faulty.

Have you tried simply grounding the single wire that goes to the fan switch to see if the fan comes on?

And what exactly are the indications that your engine is overheating? If you're simply going by what the dash gauge is telling you, be prepared to hear that laughter off in the distance again!

D43DLU5 JUN 13, 08:08 PM
I know its overheating from having all my coolant boil out from the reservoir up front once hitting the red. I dont want to reach that point again.

I can try to ground the wire next.

[This message has been edited by D43DLU5 (edited 06-13-2020).]

Spoon JUN 14, 01:09 PM
With all the wiring changes is the fan running in the proper direction?#@%?? Also have you considered the possibility of a clogged or partially clogged radiator?

I once had a non-Fiero vehicle that would overheat while sitting at a light or in slow moving traffic. After replacing all of the usual stuff it still would do the same. Long story short, the radiator was partially clogged. This was discovered by a professional radiator shop. I carried the radiator to them and explained what all I had already done. They hooked it up to a hose connection and did a flow check into a channel with a weir at the end. They could tell by the depth of the water going over the weir that the flow rate was below expectation by xx percent. Definitely old school technology but they service radiators taller than a full grown man.

You may want to have yours checked by a professional radiator shop. Weigh the cost of cleaning versus replacing if it is clogged up. And "NO",..... radiator flush in a can will not cut it. It can't do reverse flow, saturation soaking, yada, yada.

Just saying.

Spoon


------------------
"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

D43DLU5 JUN 15, 01:42 AM
Spoon,

That is a very good point, however that does not apply to my situation, luckily.

My fan operates correctly when the A/C is turned on and the car will keep cool under this condition. My problem is that my fan will NOT turn on from the temp switch.

The cooling systems works perfect aside from this one problem. Car stays cool when driving, when the A/C is turned on.

The car will overheat at idle with A/C off as the fan never turns on due to high temps. I have watched it and tested this to boiling point multiple times.