Help!!!!!!!!!!! Electrical Problem

[RRROBB]

Help!!!!!!!!!!! Electrical Problem I have a 1977 L82.
1) Fuel gage was reading 1/8 tank at all times (originally worked until I replaced the printed circut board).
2) read about the resistors on the back of gauges and moved dk blue to oil gauge//lt blue to volt meter// and then I have 2 orange or faded red resistors for the gas gauge and water temp.
3) after exchanging the blue to orange (red) my gas gauge now reads 1/2 full on a full tank.
4) no other gauge works.......the clock does work
5) I have a short somewhere that is pulling my battery down. Currently am connecting and disconnecting as needed.
6) brake lights are very weak.
7) the overhead courtesy light is lit at all times (currently disconnected)
8) I have replaced the oil pressure sender and the water temp sender.
9) I have a new 100 amp alternator it has been checked and works.
10) new Optima red top
11) I checked the battery last night and it was reading 11.42 volts
12) checked current on battery with leads attached to + post and loose terminal and read 11.42 volts.
13) I have not gone the pulling fuse route yet

ANY SUGGESTIONS????????????????????

 

[vetteboy86]

The first thing that I would do is find the battery drain. This might solve more then one of your problems.

The easiest way to do this is to connect a meter or a test light in series with the battery positive terminals. With the key off, and nothing on the light should not be lit, or no reading on the DMM. If there is then obviusly you have a draw. I would disconnect one fuse at a time, until you see the current drain disappear, you have now narrowed the search down to one circuit of the car. Once you have that, then check out the individual accesories on that circuit.

Good Luck

 

[Mr. Chuck]

Battery Drain

The first thing that I would do is find the battery drain. This might solve more then one of your problems.

The easiest way to do this is to connect a meter or a test light in series with the battery positive terminals. With the key off, and nothing on the light should not be lit, or no reading on the DMM. If there is then obviusly you have a draw. I would disconnect one fuse at a time, until you see the current drain disappear, you have now narrowed the search down to one circuit of the car. Once you have that, then check out the individual accesories on that circuit.

Good Luck

One thing to keep in mind is that you will see the current flow of the clock. The brightness of the test light should give you some idea as the degree of short / load draining the battery. One of the first fuses to pull would be the one powering the clock, on my 81 it's the CLK CTSY FUSE A 20 amp, Which also powers a bunch of thing like the "glove box light, cigar lighter, dome light, spare tire light, courtesy lights & interior light delay timer.
Also remember that some circuits are hot all the time and have no fuse to pull.
**** A note from my old Navy aircraft maintenance days; always look first at what was most recently added and/or worked on. Another easy step is to start with the units that have connectors that are more accessable. Big note is always keep a written record of what you disconnect and what was the result!! Go slow and keep good records, it is so easy to get in a rush or if more than one person work on the car at different times.

Good luck!

 

[vetteboy86]

Does the car have an aftermarket radio installed? Reason I asked is because a neighbor had a mid 70's vette that had some problems. The owner before that had a radio installed, with some crappy wiring. I was able to find the battery drain, which was caused by the new radio.

 

[RodsnRides]

vetteboy86 is spot on here.

Remeber to close the door (dome light switch) or hold the button when diagnosing. The intensity of the test light under draw is definitely something to watch when pulling fuses.

Rick

 

[RRROBB]

Thanks guys!! I'll post results when found this weekend (hopefully)