Radiator fan not spinning (Page 1/1)
ugalang MAY 09, 10:51 PM
I got my Fiero back from the body shop last week and it overheated on the way home. I had to stop and top off with coolant from a gas station to get the rest of the way home.

With a further diagnosis, I observed that the radiator fan was not spinning even when the A/C was running. I checked the fuse and it was fine. I then jumpered the relay and the fan did not spin however the A/C blower did start. I put a multimeter to the wires powering the fan and observed 13+ volts with the A/C on. I hooked up the radiator fan to my battery and it spun with no problems. I then used the car's ground with only the battery hot wire and it still ran. I know that the temperature sensor should not affect the fan if the A/C is on but I also jumpered the plug and still had no success. I also purchased a new "four seasons" relay and it did not make a difference.

It seems to me I have successfully tested everything from the wire going to the fan all the way back by seeing 13+ volts from my multimeter and then tested the fan by seeing it run when directly connected to the battery. I also purchased a new Relay just to make sure. It would seem like the fan should run from the car as easily as it runs from the battery.

I am stumped. What am I missing?
Patrick MAY 10, 12:58 AM
It would really help if people would mention the the year and the engine of their Fiero when seeking advice!

I don't quite follow what you've done. The simplest way of testing the rad fan is to disconnect the single wire that goes to the fan switch... and then ground that wire. The fan should come on.

If your Fiero is an '85-'87 with the 2.8, the trunk blower will come on as well.

And if your Fiero is an '87-'88 with a duke, none of what I've posted applies!

[This message has been edited by Patrick (edited 05-10-2023).]

ugalang MAY 10, 05:31 PM
I wanted to follow up on the issue. A couple of guys on the "Fiero Forum" on Facebook put me on the right track. They saw the issue without the need for the engine or year being part of the problem.

ANSWER: The reason I was stumped was twofold. First, My experience with Fiero's is limited to my own car so I had an assumption that my fan was set up like everyone else's. It is actually straight-wired to the fuse box with a manually adjusted aftermarket temp sensor running the to radiator. I knew enough to eliminate it from my troubleshooting but it led me down several other roads such as the relay and the fan automatically turning on with the A/C running. I give credit to Terry Hansen for pointing out that my fan is not "stock" and allowing me to think past what was in the book. The second reason I was stumped was that I thought that if my multi-meter was getting 13 volts from the wire, it should spin the fan. Zach Lee helped me realize that. After tracing my hot wire back to the fuse box, I saw that the pigtail splice was the issue. It looked well done but it must have burned out between the fuse and the wire. After re-terminating the pigtail, I was back in business. It was basically a process of logically eliminating variables.
Patrick MAY 10, 06:19 PM

quote
Originally posted by ugalang:

A couple of guys on the "Fiero Forum" on Facebook put me on the right track. They saw the issue without the need for the engine or year being part of the problem.



I guess you now know where to go for future advice.
ugalang MAY 10, 07:14 PM

quote
Originally posted by Patrick:

I guess you now know where to go for future advice.



I do know where to go. Pennck's. Do not confuse this being my first post with the first time have come here to "get advice". The reason I have never had to post is that the answers to my issues have already been posted somewhere in Pennock's. I took the time to update my own post just in case someone would benefit down the road. It had nothing to do with you.
Patrick MAY 10, 07:42 PM

quote
Originally posted by ugalang:

Do not confuse this being my first post with the first time have come here to "get advice".



You should be fully aware then that when asking for advice, the year and engine of the Fiero often makes a difference when troubleshooting. Yes, even with a rad fan issue. I stated in my first post why it makes a difference.

Also might've helped if you could've mentioned that your fan is "straight-wired to the fuse box with a manually adjusted aftermarket temp sensor running the to radiator".

You want help with a rad fan issue, yet you can't be bothered to mention your Fiero's year, engine, or the fact that it has a non-factory fan switch arrangement... all pertinent information.
82-T/A [At Work] MAY 10, 08:42 PM

quote
Originally posted by ugalang:

It is actually straight-wired to the fuse box with a manually adjusted aftermarket temp sensor running the to radiator.



Ah man, that's the worst. I always hated it whenever I'd get a project car, and the wiring had been hacked up and people did totally custom stuff. Glad you got that sorted.

FYI, this is a great link to all the service manuals and such: https://fieroinfo.com/manuals/

I highly recommend buying the individual book for your car though, I dunno about you, but I much prefer going through a book than a PDF...

You can buy printed versions here: https://www.themotorbooksto...gic.html?query=Fiero
ugalang MAY 10, 09:59 PM

quote
Originally posted by 82-T/A [At Work]:


Ah man, that's the worst. I always hated it whenever I'd get a project car, and the wiring had been hacked up and people did totally custom stuff. Glad you got that sorted.

FYI, this is a great link to all the service manuals and such: https://fieroinfo.com/manuals/

I highly recommend buying the individual book for your car though, I dunno about you, but I much prefer going through a book than a PDF...

You can buy printed versions here: https://www.themotorbooksto...gic.html?query=Fiero




I appreciate that and thanks for the link. I do have a hard copy of Haynes. It has come in very handy, especially in regard to torque specs. After I figured out what I had going on was custom, in regard to the fan, it made troubleshooting a lot easier. All of my wries were in the loom and I wrongly assumed that at least the wiring was stock. I spent two days waiting for a relay that was not even being used!
IMSA GT MAY 10, 11:01 PM

quote
Originally posted by ugalang:
I appreciate that and thanks for the link. I do have a hard copy of Haynes. It has come in very handy, especially in regard to torque specs. After I figured out what I had going on was custom, in regard to the fan, it made troubleshooting a lot easier. All of my wries were in the loom and I wrongly assumed that at least the wiring was stock. I spent two days waiting for a relay that was not even being used!



Just be aware that the link he provided has the factory service manuals which are about 1,300 pages long in case you want an actual factory manual.