1980 Wiring woes...

[Malamute]

I have my dash out to start trouble shooting the wiring in my car. I have purchased the schematic and have decoded the wire colors coming into both guage panels.

Now I don't really know where to start. Currently, none of the center guages work. Which I partially attribute to the poor condition of the printed circuit board. However, before replacing that, I would like to rule out the possibility of any faults in the wiring.

Here begins my lengthy question asking.

1. On the top of the water neck there are two plugs with an elec connection coming out of each. What are the two connections? When I hit both wires with my multimeter I get a 14v reading. How is it possible to have both a hot and a ground attached to the same piece of metal?

2. Where does the temp sending unit attach to the engine? I have a wire wrapped with another coiled wire coming out of the head on the drivers side between the front two header tubes. Is that the sending unit? If so, what is the thing supposed to be connected to?

3. With the car idling, what voltages should I be reading out of the wiring harness for the different guages?

I'm sure I'll have more, but I really do appreciate any help offered.

I'm sorry, my stupid arse posted this in the wrong section. I thought I was posting in C3 General & Technical.

 

[silver 80]

The first thing I would do is to buy the shop manual
This isn't a Cali car is it?

the two connectors on the water neck are thermo switches when the antifreeze is hot enough it turns on the switches and I think that they are for vacuum. I think one is for EGR I don't remember wht the other one is for but it is on your emission decal on the hood.

about your gauges.... did you check to see if the fuse is good it should be a 20amper

the temp sensor is on the drivers side I think it's detween one and three, if it's cut all I can say is start peeling back your wire harness and see where they cut it.

Voltage to gauges? I couldn't tell you right off hand. I'm sure someone with
a lot more knowledge than I will be here soon to help you.
good luck.

 

[Bender]

My wiring is fubar, when I brake the right tail light turns on and the left one turns off. So when I brake my tail lights blink :/

 

[8T8T2]

On my 80 one is a thermo vac. switch which when temp. was high enough would send vac. signal to another switch mounted at drivers side firewall which in turn would let the t/c lock-up work when required. The other was also thermo. vac. switch for either efe[maybe efi] or vac. advace during cold start-up. This is from memory several yrs. ago so take with grain of salt.
You had mentioned taking voltage readings from wires. One may be the electric choke, it ran from drivers side across intake to pass. side of carb.
Hope this gets you in right direction.

 

[JohnZ]

Suggest you get a 1980 GM Service Manual to help you dope it out - there are a lot of interconnected and interdependent systems with electrical/vacuum sensors, switches and relays to deal with under the hood, and you should understand what they do before you tear into it.

 

[Enigma]

I've got the 80 shop manual. If you want and I have some time I can scan the electrial section for.

Enigma

 

[Malamute]

silver 80 - No, this is not a Cali car. I have learned from previous wiring mis-adventures, always keep an eye on the fuse panel and have spares ready.

Bender - Sorry for laughing, but that is just funny. I had a fair bit of trouble with my tail lights working intermittently and just being really dim. I discovered that all 12v and ground meet is one of two junction points. When I pulled back the elec. tape I discovered that there were bare wires with a little metal crimp holding everything together. The wiring was so corroded that when I clipped my test light to the ground and touched the 12v connection, I barely got a dim light from the tester. I cut all the exposed wire out and stripped them all and then soldered all the connections. Then I covered them in heat shrink and then wrapped them in elec. tape. Hopefully I never have to look at them again.

8T8T2 - Thanks for the help. Having an idea what systems to start looking at when trying to track down mystery wires is a big help.

JohnZ - I am working hard to try and absorb a lot of info in a short period of time and get the different systems working. I'm focused on the guages as the moment. I have purchased a new temp. sending unit and from looking at a few other cars last week, I figured out the green wire I'm looking for under the hood is located in the wire loom under the drivers side drip edge on the fender. There is a Tee in the wiring loom located approximatly perpindicular to the location of the temp sending unit. Now I have to figure out where in this path the other end of the dark green wire is.

Enigma - I have an Assembly Manual that I purchased from Mid-America. Is that the same as a shop manual?


Now I have a whole new problem. I was testing the harness for the center guages when I realized there was a large lump of elec. tape. I peeled it back to discover that the previous owner had cut the harness completely out and then reconnected it at some time. The wires had all been stripped, twisted together and taped for a solid connection.:eyerole I cut that mess out and made the proper connections, except for two wires. Seems I forgot to mark the two black wires. One is the common ground and the other is part of the two wire system that operate the fuel guage. Anyone know a simple way to figure out which wire is which?

I think the fuel level sending unit is grounded at the rear of the car. That leads me to think that they are both just grounds. But I don't have my schematic handy and can't remember.

Thanks for all the help guys.

 

[Enigma]

I have the assembly manual also and its not the same as the shop manual.
The shop manual shows the Schematic for each circuit with a pictorial of where all the components are located for that circuit ,including fuse connections and troubleshooting.

Enigma

 

[Malamute]

What is the difference between the service manual and the shop manual?

Well, I had a chance to look at my scheme and figured out that both black wires run down to the same common ground point. So, it doesn't matter which one gets connected where.

 

[Malamute]

I've got the 80 shop manual. If you want and I have some time I can scan the electrial section for.

Enigma

If it isn't too much trouble, I would REALLY appreciate that.

 

[Enigma]

I'll get back to you when it's done

Enigma

 

[Enigma]

Ok I hope this works. Below are 2 files for the document and the last one is used to join them together.

http://tinyurl.com/32jtk
http://tinyurl.com/2begu
http://tinyurl.com/3eu3n

The first file will be named "Electrical+Shop+Manual.zip.001.zip"
Rename the file to "Electrical+Shop+Manual.zip.001" before using Hjsplit.

Let me know how it worked out or if you have any questions ,let me know.

Enigma

 

[Malamute]

Thank you so much for taking the time to scan that in for me. That is going to be a very big help.

I tried the center guages today and so far I have oil pressure and voltage. I know the water temp doesn't work because I have to run the wire to the temp sending unit. I'm not sure about the fuel guage since there are only two gallons in the tank.

Looks like I'm on the right track.

Thanks again.