Maybe it was wired for a different style/era relay?
74 3.0 CS wiring help
- Thread starter m5bb
- Start date
I'm sure that is possible but the design of this simple relay circuit has be around a lot longer than I have and I'm older than dirt!
The reason I ask is the old Hella can relays have different pin order than the newer square ones, they will both fit into the socket but the wires are different.
I'm sure that is possible but the design of this simple relay circuit has be around a lot longer than I have and I'm older than dirt!
Is the Trapezoid mirror original to this 74?
Not sure Chris? I think so.
That could very well be what happened Steve and good point.
That is actually what put us on to changing the relay plug wiring.
We noticed the wiring diagram on two relays were different although neither one worked.
Not sure about load shedding/changeover relay?
Working on that this AM and will report back.
Make sure they put the correct one of that in there also, post a pic of it and I can compare to mine tonight. Can't imagine why anyone would mess with that wiring.
We'll this hasn't got any better.
Thought I had some help but that didn't pan out either.
I'm on to a couple things that I think are related, maybe connected would be a better term for electrical stuff.
If I could find a wiring diagram for a 74 3.0CS that would really help.
I had no idea so much changed between <73 and then 74. Many more relays and in different locations.
So if anyone knows where to find a schematic for a 74 please let me know.
Gary
m 5 er @ Comcast.net
Thought I had some help but that didn't pan out either.
I'm on to a couple things that I think are related, maybe connected would be a better term for electrical stuff.
If I could find a wiring diagram for a 74 3.0CS that would really help.
I had no idea so much changed between <73 and then 74. Many more relays and in different locations.
So if anyone knows where to find a schematic for a 74 please let me know.
Gary
m 5 er @ Comcast.net
Contacted Classic in Germany.
They say there are CD's with schematics and manuals.
They gave me part number but did not show on look up & had to call dealer.
I've ordered one. About $100.
If it doesn't have the 74 and newer schematics its going back because classic says it has what I want.
Right now car is running fine.
I replaced all the relays as suggested.
There is one wire that connects to door light switch on drivers side.
It goes directly to the load shedding relay. When connected as found the dash key on lights are on without key?
I have it disconnected and everything works so far.
I admit I'm not an electrical guru but with a schematic I can follow and test things.
Only 129 74's built and not all of those in US so I guess the cars that are getting repairs are few and far between.
Sure not any 74 owners posting here?
Gary
They say there are CD's with schematics and manuals.
They gave me part number but did not show on look up & had to call dealer.
I've ordered one. About $100.
If it doesn't have the 74 and newer schematics its going back because classic says it has what I want.
Right now car is running fine.
I replaced all the relays as suggested.
There is one wire that connects to door light switch on drivers side.
It goes directly to the load shedding relay. When connected as found the dash key on lights are on without key?
I have it disconnected and everything works so far.
I admit I'm not an electrical guru but with a schematic I can follow and test things.
Only 129 74's built and not all of those in US so I guess the cars that are getting repairs are few and far between.
Sure not any 74 owners posting here?
Gary
Gary,
I will mail you a copy of the 74 blue book diagram. I believe that is what you'll get in the CD. There is no wiring diagram available for the late 73 coupes with window circuit breakers such as I have, bummer.
Chris
I will mail you a copy of the 74 blue book diagram. I believe that is what you'll get in the CD. There is no wiring diagram available for the late 73 coupes with window circuit breakers such as I have, bummer.
Chris
w. chen
Well-Known Member
hi folks, have been reading this thread about the a/c in 74 model years. mine is a 74 and similar to what has been discussed. my a/c fan switch turns aux fan on. this is the same scenario for my 72 tii. the aux fan comes on when eng temp gets up there though it seldom happens. (note: this doesn't happen in the tii as it does not have a temp switch in the radiator). don't know at what temp the fan kicks in, but probably close to the red line. the temp switch is attached at the bottom outlet of the radiator and it is all metal (brass?). almost all parts in a/c system is original with exception to compressor and evaporator and some lines. the wires and relays i believe have not been touched in the last 32 years i owned it.
by the way, i believe the 74 model years, 2002 and e9 and probably the e3s have trapizod door mirrors.
w. chen
74cs
by the way, i believe the 74 model years, 2002 and e9 and probably the e3s have trapizod door mirrors.
w. chen
74cs
Thanks so much Chris.
Scott Perkins thought he had one and maybe it is correct but the legend doesn't match the schematic. It has some of the other relays but still trying to decipher.
This car has the window circuit breakers as well.
I am going to buy the CD's as an investment in my car.
I will gladly share with others if that is possible?
It's amazing that they didn't produce schematics for the models as they upgraded the cars. At the time I guess it didn't matter and who thought 40+ years later we would all still be driving these cars. :grin:
I do have the car running and working very well. Drove it for about an hour today and will drive some more tomorrow. Weather permitting.
Everything works and the car starts well when cold and ok when warm.
The temp gauge will creep past half way when traffic but with AC running it does not do that at all.
I found the left license plate light was dead.
Removed cover (these are on the side of the plate instead of above) and found a rusted mess.
Was not even sure I could get bolts out.
Did manage but could not get one set screw that connect wire to light to come loose. Had to cut wires.
Put whole device in media blaster and got rid of rust. Got one of two wires out but one screw would not come out even after soaking over night with PB Blaster. Had to drill out screw and tap and install new screw to hold wire. Sprayed metal with conversion spray and put back together.
Had to get some bulbs. 12V 3 watt tube shape with metal ends.
Amazingly they had some at Pep Boys.
All back like new.
The bulb holder for the 74 year for this license plate light is not even shown on parts lookup? Only the older top mount type.
Anyhow glad to get it back to owner. I get a little nervous driving around a $60-70K car.
Thanks again and talk to you soon I'm sure.
Gary
Thanks for your input and continued ownership. Just great!
Yes, this is the same as this 74 I am working on. VIN 4310220
I'm not sure of temp when aux fan comes on but do remember the gauge was about 3/4.
So has your seat belt reminder buzzer been disconnected?
What about the ignition key buzzer.
I'm not sure how this was supposed to function?
Does it buzz if you leave key in ignition and open door?
Does it buzz if you leave lights on and shut off car?
Thanks,
Gary
w. chen
Well-Known Member
hi, the buzzer for the seat belts and key in ignition have all been disconnected. maybe even the buzzer has been thrown out.
there was an incident a year ago when i had stopped to put in gas at the station. when i restarted the car, thick white smoke poured out of the dash and dash vents. scared the crap out of me. one part of me wanted to find the source and put it out and the other part of me wanted to just let it burn (insurance will take care of it and don't want to rebuild a burnt car). eventually the smoke stopped. i was shaking and couldn't figure out what went wrong. it was dusk time and i was a ways from home. i started the car with no problem but dash lights were out, and one side of the car's external lights were out. car drove fine so i took off and went straight home. all my senses were on the alert if there was any additional smoke/fire. next day, took it to my friends garage and he discovered a wire (don't know which wire but a hot wire) had touched ground and burned the insulation off thus the white dense smoke. nothing else was singed or damaged. so i lucked out there. i should do some preemptive work on the wires but really don't know where to start.
w. chen
74cs
there was an incident a year ago when i had stopped to put in gas at the station. when i restarted the car, thick white smoke poured out of the dash and dash vents. scared the crap out of me. one part of me wanted to find the source and put it out and the other part of me wanted to just let it burn (insurance will take care of it and don't want to rebuild a burnt car). eventually the smoke stopped. i was shaking and couldn't figure out what went wrong. it was dusk time and i was a ways from home. i started the car with no problem but dash lights were out, and one side of the car's external lights were out. car drove fine so i took off and went straight home. all my senses were on the alert if there was any additional smoke/fire. next day, took it to my friends garage and he discovered a wire (don't know which wire but a hot wire) had touched ground and burned the insulation off thus the white dense smoke. nothing else was singed or damaged. so i lucked out there. i should do some preemptive work on the wires but really don't know where to start.
w. chen
74cs
Gary,
Found the license plate light, 63 26 8 777 102, not pictured but is Item 1 in the diagram which shows a bumper mounted light, used in Italy it says.
Found the license plate light, 63 26 8 777 102, not pictured but is Item 1 in the diagram which shows a bumper mounted light, used in Italy it says.
I have a 74 and a wiring diagram. I can tell you that Ive seen more than one 74 specific diagram and they differ. Anyway, Ill be with the car this weekend. Ill send you an email.
You're amazing Chris.
What parts lookup do you use?
I usually use Penske because it's easy.
I just looked at Real OEM and it's more like the dealer view.
And now I see it listed like you said for Italy.
Maybe this car went to Italy first. I really don't know much about it's history. The owner bought it a an auction. I think Barrett Jackson maybe 8-10 years ago. Paid about $30k for it then.
It's in the registry, just not much there. 4310220
Ignore the Italy reference, it just means it was used on Italian and US/NA market coupes. One of the idiosyncrasies of using RealOEM. I found the part number on eBay.
Hey David,
Got your email and thanks.
I think I may have a 74 schematic. A coupe friend Scott Perkins (rsporsche) scanned a schematic but then the legend did not match.
He went back and realized the legend was right but it was a Bavaria schematic. He will scan the correct schematic tomorrow and I will have it I hope?
So some questions you may be able to answer?
When the cars came from factory-
Did the key buzz when left in ignition and door opened?
Did dash buzz if lights were on and door was opened or maybe key still in ignition.
These are things I really don't know not having a car that is totally original.
What was the procedure for disconnecting the seat belt warning buzzer?
A year ago the car windows would not go down without opening the door.
I tried to figure it out and could not but did figure a way to make it work.
I installed another ground wire to the door switch which worked it's just didn't allow the interior light to come on with door opening. You could turn it on manually.
It went like this for 8 months or more and worked.
This car has always gotten dead batteries but the owner would not put a tender on it or an E24 M6 he had.
I've worked on both cars and just went and bought battery tenders and put them in his garage. Sometimes he does not drive these cars for months.
So in the process of restoring AC I found some issues with the relay for the aux fan. I was able to correct this problem and that is working very well. Discovered the temp sensor in the bottom right of the radiator for the aux fan turn on. My 72 does not have this.
So if you know the answer to the questions about that it will be a big help with a area that may have been changed in the past.
Today the car was running well and everything was working.
There was a brown/violet wire that went to one side of the door light switch and this one wire was causing dash lights to be on with no key.
Right now it is disconnected and I can't see any problems that has caused.
I was able to remove the jumper wire to ground and now the interior light works like it should.
Thanks,
Gary
