notabot

Hi all,

I just made a relay jumper/tester and the good news is that it worked. The bad news is that the oil cooler fans did not turn on in low speed when hooking the jumper up to points 30 and 87c (I don’t know the technical term). However, they did work on high speed (30 and 87).

I’ve come to find out that it can be pretty dangerous for the low speed to not work as the oil has to get mighty hot before the high speed turns on.

Anyway, after some admittedly brief Googling, I can’t find the answer to this question. Which resistor is the culprit? Driver side or passenger side? Or both?

Also, since you’re already here reading this, what can I do to fix this? I don’t know how to solder and thinking about Ohms and amps makes my brain leak out of my nose.

Thank you,
Brandon

Railmaster.

Passenger side resistor if a LHD car. Serach and find information, an easy DIY or let a garage fix it.

pp000830

Hi Brandon,

Don't freak out too much as my low-speed fans for both the Oil Cooler and the AC condenser hadn't worked for years until I stumbled over the issue using jumpers recently. My engine didn't explode and the AC ran strong. I have read some folks suggest removing the bumper cover to replace the oil cooler resistor a big job, others go from the wheel well side disturbing a cooler and the lines going to it on a 26+year-old car.

Both options seemed more invasive than just relocating the resistors. Also by relocating them & replacing the OE with industrial resistors I feel makes for a more robust solution at a much lower cost than the OE items. they can be inspected or even replaced if needed at any time.

My fix below has only been in place for a few weeks now, hot summer weeks, and I hear the fans turn on from time to time on 90 degree + days. I guess the DIY replace and relocate fix I did will need to be in for a few years before I can really say how robust it is.

You may have already seen these:

https://993servicerepair.blogspot.co...wer-speed.html

https://993servicerepair.blogspot.co...ooler-and.html

Hope this helps,
Andy

notabot

Hi Andy,

I was hoping you’d post here. Unfortunately I’m not experienced with soldering or any of that stuff so I just bit the bullet and bought an OEM resistor. I’ll do the relocation instead of outright replacing it.

Does the AC condenser resistor need to be replaced at the same time or can that be put off for another time?

mike cap

Pull off the bumper cover do it right. Replace both resistors. If one is shot the other is not long. The new replacement resistors are more robust and will last the life of your ownership. Plus you get to clean out the heat exchangers, replace the foam air duct pieces. Bumper cover on and off is easy. You may even tidy up the fender welting and do a bumperette delete. Lotsa fun to be had.

notabot

Is the A/C condenser fan resistor part # 993-616-521-01?

Is it the same part number for each side?

Railmaster.

Tell me more about the upgraded resistors! When were they introduced? Changed mine in 2015, new or old?

pp000830

Sounds like a plan!
Yes, I would replace both as I am sure the condenser resistor is well on its way to failure if it has not been replaced.

On the driver's side, one can get to the pigtail plug of the old resistor easily, it sits along the inside wall of the quarter panel (frunk side.)
On the passenger side, you will see the wire in the same location but the plug is a bit too far forward to see. If you pull the headlight pod you can see the wire and the just pull on it towards the rear of the car and it will unplug and release from the old resistor's pigtail. By doing this you can abandon the old resistor and will avoid any additional disassembly to retrieve the socket that is part of the wiring harness leading to it.
Pick a good spot to mount the resistor to metal as it is only rated at 55 Watts and so will likely need to be mounted to metal as a heat sink. If more convenient one can fabricate a heatsink out of 1/8" thick x 2" aluminum flat bar stock from a DIY store acting as a heat sink and can be bent into a mounting bracket at its ends offering greater flexibility in picking a mounting location and attachment points. Minor mechanical engineering involving a hack saw, a Channellock pliers, and a drill bit. On the upside, once you find a good way to mount it you can probably use the same position on the other side of the car for the other resistor.
When done take some pictures of your handiwork and post them here, enquiring minds want to know!
Think of this above a car therapy, something to enjoy!

Andy

mike cap

Same pn each side.

Uograde was a million years ago. Mine were new style and that must’ve been ten plus years ago. There’s a thread around somewhere that compares old versus new.

rwestervelt

If it is very hot where you live and you are worried about high oil temperature, you can temporarily unplug the temperature sensor on the oil cooler. This will cause the fan to run at high speed when the motor is running.

I live in a hot climate and even with the system working properly, I felt like the low speed fan did not come on soon enough. I decided to install an oil cooler fan override switch. The system works normally until the switch is flipped. On hot days, I can run the oil cooler fan at high speed with the flip of a switch.

notabot

I live in Texas and the temp gauge can get pretty high if I end up sitting in traffic any time past 11am.

About the fan not turning on soon enough, I purchased this cable to help with that issue because I didn’t wanna install a button: https://rennlist.com/forums/964-foru...ooler-mod.html. You can save yourself some coin if you’re like handy like Andy, but I’m not so I have to pay the piper.

pp000830

Yes, did a run in Houston being trained on the Project Accounting module in Oracle Business Apps. Was during the summer. We be talkin' really really hot and its a humid heat. No one on the sidewalks outside, would probably melt your shoes standing on them.

My view is any time the temp gauge is at 9:00 or higher one would think the oil cooler fan should kick in, but it doesn't always.
At 9:00 and beyond the oil pressure at idle can dip below the 2 bar mark. My feeling it's got to be rather hot for that to happen.
Also, I suspect as soon as one starts moving the added cooling provided by the fan is negligible, but standing with no air flowing through the oil cooler, its effectiveness probably drops to zilch.

Andy :-)

notabot

Not sure how accurate this picture is, but one time it got to that 248F mark while sitting in traffic, and a little below that mark is when the high speed is supposed to turn on.



https://www.pelicanparts.com/techart...ubleshoot2.htm

edit: not a fan of the 8 o’clock/9 o’clock speak since it’s not a full clock face

Railmaster.

A resister is one who resists, one who stands firm against something, refuses compliance or withstands temptation. A resistor is an electrical component that resists the passage of electricity. ... It is used to control electrical current.

pp000830

Yes, I type it wrong most of the time and go back and fix it.
Andy ;-)