ok boys, on my 86 IROC, TPI (vin F ) with a single fan set up. theres SUPPOSED to be a fuseable link in the power source from the bat+ to the fan relay. it is MIA. so I have a weather proof inline fuse holder in its place.with a 40a fuse. I understand this is not acceptable. the FSM specifys a .5 fuseable link there. my question is ,,, .5 WHAT?? I would really rather have it as correct, but all I get is blank stares when I try to buy a replacement fuseable link in,,,, .5 . wth??? can anyone elaborate?? what can I do to have this correct and functional?? HELP!! I don't think my 305 can stand another 310F adventure due to fan failure.

 

No fusible link on my 86. It has the weatherproof inline fuse holder you describe. Pretty sure it's a 30A, haven't blown a fuse in 15 years.

 

I don't know why a 40A fuse wouldn't be sufficient newer vehicles with relay triggered fans don't have fusible links-just relay protection. If the fan draws anywhere near that much current, I'd say th fan motor is shot. Heck even a Mark VIII fan on HIGH speed draws on average 24-26 amps from my experience and its easily three times the fan a stock TPI single fan is.

 

Diagram shows a fusible link, but as I said mine has none and the weatherproof inline fuse holder you have. May be another one of those some have it and some don't things the general did a lot of on these cars.
http://92b4crs.tripod.com/86wiring/86wiringindex.html

 

ah ,thanks , mr tag! just for s&g im gonna get a new fan motor. I now am believing that the motor is drawing too much current,thusly blowing my fuse. again thanks Mr tag rocks!!

 

YQW But check all your connections before getting the fan. Pull the connectors and look if they're burnt/loose/getting poor contact.

 

The ".5" refers to a metric wire size. A metric .5 is equivalent to a 20AWG.

Refer to the Repair Procedures section of your Electrical Diagnosis supplement to your FSM.

Also, running a fusible link longer than 9 inches does will not provide adequate circuit protection.

It is not recommended to replace fusible links with a fuse. The fusible link is designed to protect the wire harness between the power source and the device(s).

Why the discrepancy between the FSM and what's on the actual car is anyone's guess.

 

Right:

.5 is the cross sectional area of the wire, in sq mm.

Generally, fusible links are only intended to protect the wire, not the load. They are usually about 3 - 4 gauges smaller wire (around 40 - 50% of the CSA) of the wires they are protecting. But not always... as in this case, the FL is only 1/6 the area of the wire; so evidently they used large wire to keep the voltage drop low, and sized the FL to protect against faults in the load.

 

No fusible link was removed, this is factory equipment. I opened it up and looked and it's a 20A fuse, been there since I got the car.

 

That's for the fans? May I see how you have it wired?

 

 

See the component diagram below:



As far as I can tell the circuit diagram and the component diagram don't match. Maybe it does, but I don't see it.

Edit: That 20A fuse (In Line Fuse No. 2) attached to the fender has nothing to do with the cooling fans. It's there to protect the voltage regulator that's inside the ECM.

 

Touche' Appears it may have had one at one time. The car was 13 Y/O when I got it. None the less, I am confident the circuit is protected as it stands. 1 foot of wire at most shielded by insulation and plastic loom from abrasion, never drawing more than 20 amps.

 

update, I removed my fan and, indeed, the fan motor was shot. thusly. it probably was drawing too much current.as for the inline fuse holder I have powering the fan relay. I used a 12 gauge wire one.which matches the wire gauge of the relay wire,its the kind with a rubber cap. so far so good. but today im gonna drive it about 80 miles to see how it will perform.

 

Sorry, but can I see more of it In the car. I believe mine is hooked up wrong. The diagram is nice but I'd like a real photo. Thanks again.

 

All tucked away in plastic loom, you really wouldn't see much you can work with. And I'll apologize for that diagram, that's for a home made fan circuit with a standard bosh square relay with different pinout numbers. But the function is the same. They are pinned out to A, black and red 12v+ Supply to fan, E,orange 12v+ constant from the inline fuse in the former post, F, Green/white ground signal from the ECM & coolant fan switch & D, brown 12v+ hot with ignition on. My ECM was removed which had complete control of my fan so I had to take the connector from the coolant fan switch and run one wire from it to ground and the other to the green/white signal wire on the relay. I believe some fan switches are one wire and ground through the body of the switch. I have yet to work fan on with A/C into the equation, but I will probably have the compressor hot trip a relay to ground the signal wire on fan relay or reverse polarity on the coolant fan switch and have the relay grounded constant and use the hot from the compressor clutch with a diode inline to trip the fan relay. If this is too confusing or colors don't match what you have, tell me your setup and I'll help all I can.

 

Before ya drive, save some gas...just let it idle for an hour...less gas and a bunch more "fan workout" than a drive (unless stop and go) will get ya

 

That is a Delphi metri-pack 630 style weatherproof fuse body and cap. I know this because I stock those for use with my headlight relay harnesses. It is a factory circuit design and you won't find those in any parts store-unless you build harnesses its not a very common connector-its a handy inline style fuse holder that can be mounted anywhere and uses a standard spade fuse.

GM circuit diagrams are pretty generic sometimes...it can be difficult at times trying to decipher how they designed it in the first place. 20A seems right for a stock TPI fan in good shape-but, as I've said before those fans are barely adequate even for a stock 305 but hey, it was the eighties....the age of HO factory fans was just around the corner.....unfortunately for the 3rd gens, they wouldn't see them.

 

thankfully, problem solved ! the fan now blows harder than before and seems to be spinning faster as well. no melting fuse holders . no boiling coolant .