If you live in Vegas the mod to have the fan on whenever the AC is on is highly recommended - I think you will need it. If you do ever convert to R134a you will absolutly need it or you may damage the system from overpressure.

You have to remember that when the 928 was introduced cars looked a lot different and a single removable panel modular/removable element fuse & relay panel like this was quite a marvel - like something out of Star Trek.

Here is a picture of what a '77 Camaro/Chevelle fuse box looked like for comparison:

http://www.chevelles.com/showroom/da...e_fuse_box.jpg

People look at the mass of grey wires on the back and think its bad. Actually making them as short and direct as possible looks crappy but is a good thing. Keeping it simply wired gave Porsche lots of flexibility to do YTY changes - and they did. Porsche didn't design this for owners to mess with - so they just used grey wires everywhere - this was a very expensive luxury car - if you could afford the car you could afford to take it to a factory trained technician... (so they thought - and it was probably true for the first 5-10 years) so a very reasonable choice.

The good news for us is that though daunting and intimidating - its all fixable - the modularity helps, you can change any connection, replace any terminal, swap out any fuse block or fuse terminal, any relay socket or any plug connector. Also excellent is that you can easily take the whole thing out and do any work needed in comfort in a chair at a table rather than laying upside down crammed into a footwell with your back in agony.

There is also expansion room built in for additional relays, fuses and connectors (there is always even a whole spare unused plug available)... Its actually great. A modern VW fuse panel with any issues is a throw away & replace the whole thing deal - and has no expansion opportunities at all...

So to me it was and mostly still is a great design - the biggest issue is that they are all now about 20-35 years old - so they are more brittle & generally more oxidized - so we need to be careful.

Now placing it right under the bulkhead penetration for the blower motor recirculator box with no drip protection may not have been the smartest move...

Alan

Well I am, Learning Electrical much better then Ever Before ! It seems easy for me when you have a Expert Guide Thanks Alan and others . My Hands on is much better then reading the Electrical Schematics from a manual not that would be impossible to perhaps someday surmount .
Yes ! My Own Take on the 1980 Yr Model is that in fact the Wiring itself is just fine with the exception of : The Printed Circuits ( Dash Pod Area ) is weak at the Hookup Points . The Connections from Relays to Wiring Connections ( Copper ) Corrosion /. then Rust .
( if your very careful you can avoid damage to the Printed circuit > Watch the hook up points )
I am in agreement with Alan the the Basic Panel Set up is indeed well done for Its time with room for expansion and the fact that "indeed the Panel is repairable when damaged " That's a Huge plus side
The Panel Needs Maintenance that's all 30 Min's a Year should do wonders .
A Tip on Relays You can many times remove 1 Relay to get to the Next Relay and so to the next one and so on . When one is removed it makes it more possible to insert a Pry Tool to Giggle the next relay Helping Its removal .
So Once My Compressor Wiring ( Now in order and Indeed working ) is behind me and the New Dryer in Hand with some R12 ( about 3 or 4 Cans )
I can try to change out all the Seals and inspect the Compressor Pulley for signs of oil from that seal IE " freon Leakage "
I can Move forward and try to find a AC Expert to Leak Test the system and do a a vacuum Test on it for about a hour or longer .
This chart seems to be about right
R12

1978-1979
R12, 950 grams or 33.5 ounces

1980 - June 1988
Revised Factory recommendation,

Single evaporator systems R12, 1050 grams or 37 ounces
Dual evaporator systems R12, 1200 grams or 42.3 ounces

July 1988 - 1992
Single evaporator systems R12, 950 grams or 37 ounces
Dual evaporator systems R12, 1150 grams or 40.5 ounces

*before you attempt to charge using refrigerant weights
stated above, always check in the engine compartment for
the factory R12 sticker, and verify the charge using an
R12 Pressures and Temperatures Chart

R134a

1978-1982
R134a, estimated 807 grams or 28.5 ounces

1983-1992
as per TB, 9501, 12/19/1995

Single evaporator systems R134a, 860 grams or 30 ounces
Dual evaporator systems R134a, 1030 grams or 36 ounces

1993 onward
Original Factory recommendation

Single evaporator systems R134a, 860 grams or 30 ounces
Dual evaporator systems R134a, 1050 grams or 37 ounces

*before you attempt to charge using refrigerant weights
stated above, always check in the engine compartment for
the factory R12 sticker, or an R134a retrofit sticker,
and verify the charge using an R134a Pressures and Temperatures Chart

There is another thread active now... I wouldn't remove relays (or anything) unless you have to - e.g. focus on known/suspected issues not just routine PM - too much risk of damage & degradation to do that (exception is: do routinely clean the ground points). You may need a lot of work to catch up the panel now - but don't turn it into an annual ritual - just aim to keep it all dry & protected.

There are some other issues with the panel: Porsche didn't always put all the fuses there... (tucking the 2 central lock fuses behind the panel was weird). The power feeders to the panel are done wrongly and are not fused - its amazing there aren't more issues due to that.

Alan

I Could not agree MORE :
I Also read this
"
Another problem with the electric cooling fan is that the refrigerant temperature switch seems to be ineffective. It would be better if the electric fan ran any time that the A/C compressor was operating. One way to accomplish this would be to install a heavy-duty in-line relay, triggered by the A/C compressor signal, to operate both the compressor clutch and the cooling fan. A diode should be used at the fan, to prevent triggering the compressor when the temperature switches operate the fan.
************************************************
However Just How is the best way to do this ?
Let's see it says install a
(1) in line triggered Relay Question ? What sort of relay would that be ?
(1a.) just what size wire and from where should I run it to this relay ?
(2) Triggered by the AC Compressor signal . Question that's the Hot wire to the Compressor yes ? But that wire ? does it trigger also the cooling fan ?
(3) Now this Diode ? Question what sort of Diode ? Type ? / Model / Link to Part ?
(3a) is this correct in a 1980 Model YR ? the signal wire to the AC / Idle control Signal also signals the Cooling Fan ?
I thought the Cooling Fan was controlled by some Temperature Control . The Guy Mentions this
"prevent triggering the compressor when the temperature switches operate the fan."
Alan any Directions you can give to set this up would be great .
I Understand the Diode Idea But have no Idea what sort of Diode they are talking
Now the Relay Just what sort of Relay would be good for this ? Not familiar with a In Line Relay Types
So This Diode allows the Power signal to go to the Fan but Not back from the Fan ? or do I have this all wrong ?

Yes you use the compressor clutch activation wire to activate the relay. An in-line relay is just a normal automotive relay used in close proximity - placed in the engine compartment in this case. It also implies a serial connection - but that makes no sense here - miss-used term.

I'd suggest you use a weather sealed 30A SPST or SPDT relay like a hella:

http://static.summitracing.com/globa...7794321_xl.jpg

http://static.summitracing.com/globa...-H84709001.jpg

Easy to mount and use - Screw the case to something and wire using the pigtail - use 12 AWG wire.

See if pelican has them.

You can just connect this relay in parallel with the exisiting fan relay to drive the fan (via terminals 30 & 87) power it from the jump post (on 30) and connect to the fan motor power terminal directly (on 87).

Connect the coil to the compressor clutch wire (86) and also to the starter solenoid signal (85) connect this to pin 14 (Yellow wire) on the 14 Pin connector @ jump post. You can use 16AWG wire for just these 2 connections.

You don't need a diode unless you plan to use only the existing relay.

Operation: fan works as normal - except it also comes on whenever the compressor is on (this is only active when ignition is on). This also turns the fan off when the starter activated - this is what you need.

There is a different modification to protect the small AC clutch relay in the head unit in later models - you don't have this - you have a switch in the head unit for the AC Clutch relay - so no need.

Alan

Sound's Great Yes a Hella I remember that Hella Brand is a good one
I shall Wait until I get the Air Con activated first I Guess so that I can see if the Cooling Fan is working at all by the Normal Means I suspect the temperature Control cuts it in and Out .
I don't know yet just where the Temperature Control is, have not looked for it yet
I Have the Air Con Relay Jumped just now as that Relay was rusty and with some broken Prongs. Bought a Small Size Car Trailer and shall Haul that Porsche to Vegas soon rather then drive it as I need the PU Truck anyway. The Gas Cost saved well pay for 1/2 of the Trailer $400
In Fact I Picked up a Handful of Relays in Santa Rosa all original OEM along with a Idle Control Valve also OEM the one that speeds up the Idle when the AC is on a Vacuum Valve with Electoral Innards . Powered also by the Compressor How Wire. Just happened to see some Very Old Auto wrecker Yard and walked in and asked if the Had a 928 ? Sure enough a 84S in fact I Got the Mint Door Panels ( Black in fact ) / Glove Box / Relays/ Idle Control Valve . All the Attaching Hardware as the Guy Larry the owner let me pull everything my self i n fact and Evan Left me to do it with my Wife all alone with no over the shoulder eyeballs lol
I well get the Inflatable Spare Tire / door Jam 928 cover / and the Rugs when I pass through again in a few Days to Vegas as all that stuff looks to be in good condition . Darn the Windshield is Cracked however . He was Amazed I pulled the Parts in about 15 Min's and sold everything for a Very Low Price $100
Thanks for all the Electrical Guidance and support I really want to Hook up the Fan to run with the Air Con on all the Time . This well Happen and I had a feeling you would have a Simpler Solution Then I had Previously Read of

Sounds like you did well at the scrap yard - nice find (and very good prices). 20th street here in Phoenix has lots of 928's - but that means they know what stuff is worth... (but its usually in pretty good condition). The owner - (also Larry) drives a GTS - so he really knows....

If the car is running you can do this mod even before the AC is fixed and you should be able to tell that the AC head unit controls the fan correctly, no need for the AC clutch/Aux air valve to even be connected for this to work.

Alan

Car is indeed Running and seems to run well so far but the proof is in the Pudding lol
I shall Register and get Re- Plate it soon perhaps tomorrow and take it out for a Better run .
I Jumped the Relay because I wanted to test the AC Compressor was indeed working when I Pushed the AC Control Button. Yes it Kicks in but I only let it run a few seconds .
( First I turned the AC Clutch by Hand and it was Very Stiff at first but loosened right up after a few turns to a lighter drag )
" Idle Control Valve " The Latter 1984 Type rather then 1980 Type is much improved .
At the Bottom of the Idle Control Valves the Hook up point for the 2 wires
The Early 1980 Type has a exposed Reddish Brown Color Bakelite circuit board at the Bottom of the Switch with the 2 Prongs sticking out for the Wire Hook up. When Pulling the Wire Clips apart the Bakelite just broke all apart and left 1 single wire per hook up sticking out of what was left of the bottom of the switch lol ( Not worth a try to repair I thought )
The 1984 Type is Solid Metal at the Bottom so when you pull the wire Hook up they can't just brake all apart .
Not sure what Year they Changed that ?
I Bought the 1980 928 although the price was right because 1980 Has no Air Pump !
and the associated smog equipment and also because the wiring looked Good except for corrosion at Hook up Points .
Yes Back on topic :
I was thinking I could hook up the Air Con Fan Now and Perhaps I well . What I was really trying to achieve was to see if the Temperature control for the switch works at all ?
Now I am not sure if that's what controls the Cooling Fan to go on and off or not but was Just thinking it must be something like that ?
On the other Hand a Moot point if I wire it all to work when the AC Compressor is on and off when it is off so who cares I guess .
For me to resurrect a Car is as close as I well get to Build a Car at this point lol

Stock configuration is that either the coolant temperature switch or the refrigerant temperature switch can trigger the fans to come on. Seems there are issues with the refrigerant temperature switch working well. Its better if the fan is always on with AC - if the temperature switch is working properly it won't be off much of the time anyway...

Its impossible to test the refrigerant temp switch without a working AC and even with a working AC its a very indirect and ambiguous test - if you have dual system pressure meters on the AC low/high you could tell - otherwise it's a best guess.

Alan

Alan :
Drove the Car up the Coast and back some miles and it runs very cool . The Radiator is Newish and the Motor feels cool under the hood after driving the gauge only picks up to about 1/4 of the way up. I have not replaced the Cooling fan relay yet so don't have a clew about the electric Fan cutting in premature or not . I shall proceed with the Inline Relay Idea for the Fan related to the AC Operation . Not sure if I " like the Made to Bleed " Air Conditioning Hoses that require more Freon then normal as it has a planned leaks out . Humm Perhaps a Solid Metal Hoses would be better
The 1980 run's great by the way i was Very Impressed with the handling but the Power after sitting all those years is overwhelming , comparable to my 3.6 C4 911 somewhat
Thanks again for the great help

If you only get 1/4 way up the temp gauge after a long run something is up - maybe the gauge/sensor or maybe the fans are in fact on all the time (check?).

You should be above 1/2 closer to 3/4 on the temp guage.

Alan

Perhaps the Thermostat is missing ? However the way the Radiator ( a New one ) filled when I flushed it and installed New Anti Freeze gave all the signs of having a Thermostat
IE: Needed more Water after the Motor running warmed up some 2 or 3 times .
Remember the early 1980 Cars with little almost no Smog (Like no Air Pump) require much less heat to run smooth. As A former Smog Inspector I Know as they piled more and more smog Cra* on was to > See Below <
the best way to make it still run smooth at low speeds and Idle was to the heat the engine . This of course shortens the life of the engine considerably
My 97 F250 Gas Model Truck ran so hot i jerked the 195 Thermostat and Installed a 160 Thermostat now it runs just hot enough for reasonable Heater conditions.
I also jacked up the Ing Timing and my Fuel Millage improved as well as the running performance. Those Ford Trucks have a 5 Degree retarded Camshaft instal also as a smog Issue and run poorly related to Performance.
I well sometime get a Cooling Fan Relay 928 615 111 00 78 to 81 YM
then I can Test the workings of this Fan coming on or not .
When I also get a Gasket Perhaps I well Pull the Thermostat housing and have a look
I see Can's of R12 for sale in San Diego humm perhaps if someone shipped it to me it might blow ?
http://sandiego.craigslist.org/csd/pts/4283594879.html

If the thermostat is missing on a 928 you will likely overheat (it works differently than most cars) - so it isnt that.

A lower temp thermostat is not a good idea on a 928 - it wants to run rather warm.. its a Porsche thing... (remember the air/oil cooled legacy = hot engines).

A lower temp thermostat helps nothing - if your max cooling capacity is insufficent you will overheat regardless of the thermostat temp (you will just run less efficiently most of the time) just stick with stock temps.

Alan

Thanks for all the help everyone with my Air Condition Wiring / Controls . Was a great Help to get it set up for Charging and such . Saved me a lot of time .
Not being a Porsche 928 mechanic Per say.
As For my Car running Cool I like that Way as it does not have a bunch of Smog Junk the later Cars Have. Like no air Pump and a bunch of retarded Parts
Their is nothing wrong with the way Its running Temperature wise it runs just like Most cars I have owned . Performs just fine and most certainly does not need to run hot.
Water Cooled Cars do not like Heat Long term in my Option . However if you have a model with a lot of Smog then you don't have a lot of choice do you
they don't like to Idle with all that Smog so they Heated them up
Your welcome to delete My Posts if you don't like them I could really care less.
After working for many Dealers for many Years I Think I have a handle on things Evan tho I am not a Factory Trained Porsche 928 Mechanic .
The End lol

"Your welcome to delete My Posts if you don't like them I could really care less."


Why would anyone want to do that, this is a very educational topic, lots of good questions and info here.
Good job fixing your ac.

Who suggested deleting posts here? what is this all about...?

Alan