86 K10 electrical problems

[86chevy88]

Hey guys,

So I picked up this 86 K10, 350 w/4speed manual trans. Everything appears pretty solid except for anything that has to do with power.

Power windows are super slow, blinkers are slow, hi and low beam signal is backwards, gauges fluctuate when turning headlights on and off, the list goes on.

So I am going to start the long journey of killing each of these electrical gremlins one by one.

First off, Id like to start with grounds and that is my first question,

Where exactly should my grounds be. Battery to block? Battery to frame? Block to Frame? Body to Frame? etc. I just want to cover my bases starting from the "ground" up

[86chevy88]

No input from anyone?

[geezer#99]

Speed up your idle and get your voltage regulator in your altenator working first.
If everything works better then you know it's the altenator not charging enough at idle.

[Wgesnerjr]

I have the same questions about the ground straps. My truck came to me with no engine in it, so I have no idea what was stock. For all my investigations, This is what I have determined. Take them for what they're worth.

1. Negative batt cable. Goes from battery to engine. Where, I don't know. If its like all other Chevys, i suppose it goes to the alternator bracket. Also has a pigtail that goes to the core support.
2. Ground strap. Goes from firewall near the a/c box to the engine. (I guess. Again, no engine)
3. Ground strap. From bed to frame. On the underside near the front passenger corner of the bed. Actually saw this one in place!
4. Ground strap??? There appears to be a spot for a ground strap on the frame below the drivers door. However, it is missing on my truck. Looks like there was one at one time and it is outlined by dirt, but is not there on my truck. Could be stock, could be aftermarket, who knows?

Not sure how the frame gets a ground since the engine, cab and core support are all in rubber mounts..but it is grounded so it happens somehow.

I would also check for loose connections at the battery, alternator, starter and firewall bulk head connector. If you wiggle any of these and see lights get brighter or weird things happen, that might be your problem.

I once had an old Catalina that had electrical problems and slow starts. Turns out it was a loose main battery cable at the starter. I was leaving work and started my car when someone saw sparks coming from the underside. It was pretty scary to watch. Tightened it up and solved my issue. Just a thought.

Let us know how it goes.

[Dannyboy1966]

Originally Posted by Wgesnerjr

I have the same questions about the ground straps. My truck came to me with no engine in it, so I have no idea what was stock. For all my investigations, This is what I have determined. Take them for what they're worth.

1. Negative batt cable. Goes from battery to engine. Where, I don't know. If its like all other Chevys, i suppose it goes to the alternator bracket. Also has a pigtail that goes to the core support.
2. Ground strap. Goes from firewall near the a/c box to the engine. (I guess. Again, no engine)
3. Ground strap. From bed to frame. On the underside near the front passenger corner of the bed. Actually saw this one in place!
4. Ground strap??? There appears to be a spot for a ground strap on the frame below the drivers door. However, it is missing on my truck. Looks like there was one at one time and it is outlined by dirt, but is not there on my truck. Could be stock, could be aftermarket, who knows?

Not sure how the frame gets a ground since the engine, cab and core support are all in rubber mounts..but it is grounded so it happens somehow.

I would also check for loose connections at the battery, alternator, starter and firewall bulk head connector. If you wiggle any of these and see lights get brighter or weird things happen, that might be your problem.

I once had an old Catalina that had electrical problems and slow starts. Turns out it was a loose main battery cable at the starter. I was leaving work and started my car when someone saw sparks coming from the underside. It was pretty scary to watch. Tightened it up and solved my issue. Just a thought.

Let us know how it goes.

Here is a list of the ones I have found on mine
1) negative cable from battery to alternator bracket
2) pigtail on negative cable to a connection on the front cross support that has all the headlights in it and the radiator.
3) from firewall by the a/c housing to the engine block
4) engine block to frame, mine is on the driver side
5) frame to underside of cab, could be on either side
6) frame to bed right front corner, or one of the rear corners close to the lights
7) 2 under the dash from the firewall to the to the underside of the dash, one of mine was close to the ashtray, the other was behind the instrument cluster
Hope that helps with the grounds. as for slow windows, open your door's up and clean and re grease the guide tracks. I used a silicone based grease on mine, they work like new.

[86chevy88]

Here is an update for anyone interested.

I discovered my alternator was going bad, so after putting a fresh one on, most of my electronics seem to be working good.

I still think Ill need to grease my window tracks as suggested, and I still need a new wiper motor.

Lights and flashers returned to normal after replacement of the alternator.

Thanks everyone for the help and input!

[hatzie]

Might or might not need wiper motor assembly. Most can be revived with a little elbow grease and patience.
There's a GM Service Training Group (STG) textbook on wiper systems with some fairly serious troubleshooting and diagnosis guides in my manuals post below.
According to the table in the last few pages... The sections that apply to our CK trucks are;

• STANDARD ROUND MOTOR
• STANDARD NON-DEPRESSED PARK ROUND MOTOR
• NON-DEPRESSED PARK ROUND MOTOR PULSE