OK, this should be simple - but need some pointers troubleshooting.

On the 89' 951, my #1 cooling fan blows a 30amp fuse as is tries to switch on. #2 cooling fan works fine on a recommended 25amp fuse. So, short somewhere right?

Q1) Is the power and ground going to both fans from the same source? (probably not if they are on different fuses).

Q2) Could it be the cooling fan relay, even though 1 fan works properly?

Q3) my fan relay is part #944.615.104.03. Will relay part #944.615.104.02 work? These relays aren't cheap...

Q4) I was thinking about swapping the electrical cables from #1 to #2 and visa-versa for troubleshooting, then see if fuse still blows. Good idea?

Other suggestions?

Thanks
Greg

 

I suspect that with 150k miles on the fan that the fan motor is binding and taking huge current to start up. I don't know how easy the motor would be to rebuild.

I give the motor swap idea a shot to confirm then chase down a newer used unit to replace.

 

try spinning the fans by hand, they should both spin easily.

 

If the fuse blows immediately, probably a short, in wiring harness or in fan motor windings. If it blows after a little while, probably bad bearings. Spin the fan blades by hand to check bearings. Reversing the wires is a good idea to check wiring.

When my driver's side fan bearings went bad at 101K miles, the extra current draw cooked the insultaion off the wires at the fan resistors. This would be a good location to look for a short. They are located on the outside of the fire wall to the right (passenger side) of the heater blower fan. They are two white ceramic disks on an aluminum heat sink. You have to remove the black plastic cowling over the heater to access them iirc.

 

Thanks Waterguy. Things to check out today.

Over at Pelican Parts website, it says to check fan before removal by applying 12V directly to the fan. That's my next step. The wire swap wouldn't work - wires too short. Funny, Chilton's said to just drop the fan unit from the bottom. Well, that works fine for the N/As. My 89' Turbo will require dropping the A/C motor to get the unit out...

PITA

This looks so simple, but is taking longer than I wanted to spend.

After I try the direct wire tip, I'll post again. I'll make sure not to apply current too long - so not to burn the insulation as you suggested. BTW, the fuse is blowing instantly. The #2 fan turns a lot easier than the #1 that is blowing the fuse. I'm hoping it's motor/bearings and not wiring/shorting.

Thanks for the inputs.
Greg

 

The wires shouldn't be too short to swap (just unplug both, and switch the plugs), they may be tightly zip tied, but cutting that's not a problem is it? Are we on the same page here?

Ditto for dropping down the housing, A/C compressor removal is not necessary, from what I recall that's not necessary to remove the radiator either, unless you're trying to move both of them together.

Let us know how this turns out.
Ahmet

 

Also, if the right amperage use is in (is it?) burning the insulation off the wires shouldn't be a problem.
Ahmet

 

I just did the direct to battery test as Pelican Parts suggested. The #1 fan barely moves. #2 spins freely. That tells me the bearings are shot on #1 fan. I have about 3 ties on the wires cut already, too short. At this point, I'm not going to bother shooting electric and I will get a used fan to install. I checked out both the 83 and the 89, the 83 has no "obstacals" in the way - 6 screws, out drops the fan -easy. The 89 is too tight. The frame has 2 metal extenions that the lower (wind effects) spoiler screws in to. These 2 tabs force you to come about 2-3" towards the motor to remove the fan assembly (not the radiator too). This 2-3" puts it right against the A/C compressor with no wiggle room. I don't see any way to remove exept by dropping the compressor (sigh).

Thanks for the inputs.
Greg

 

Hey TurboTime, I have an 89 951, and am experienceing starting problems. I need to know where the line from the Fuel Vapor Purge System plugs into.
Sorrry for stealing your picture, but it's the only 89 951 engine pic I can find.

 

Cyrus951, wish I could tell you. I would refer you to an expert. I chased two black hard tube lines back to vacuum pots that are interconnected to the FPR. I still got lots to learn. I assume you checked all the obvious things. Sounds like you narrowed it down to fuel regulation. Replace the DME (fuel pump) relay? My 83 has gone through 3 in 10 years.

 

Cyrus951, here's a diagram of the vacuum hoses:



Your car may not have the funky venturi-Y under the intake-manifold to generate vacuum for the brake-booster.

TurboTime, I find it's easier to just remove the fans from the top. Have to undo the intercooler pipes & J-pipe & K&N filter, but that should be all you need.