Cluster Gremlins!

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Fless

Staff member
Super Moderator
Joined
Apr 2, 2017
Posts
12,172
Reaction score
24,845
Location
Elev 5,280
Pull battery, charge, and have it tested. Inspect and/or replace main battery and alternator cables. Inspect and clean engine and body grounds.
 
OP
OP
Dakcbeast

Dakcbeast

Member
Joined
Sep 11, 2021
Posts
46
Reaction score
30
Battery is new. Going for grounds today. On ramps and blanket on the gravel! Is there a schematic of some sort to show me where all of the ground points are? I know a few tough ones are on the back of the intake to block, but WOW are they hard to get to. Thank you sir.
 
Last edited:
OP
OP
Dakcbeast

Dakcbeast

Member
Joined
Sep 11, 2021
Posts
46
Reaction score
30
Pull battery, charge, and have it tested. Inspect and/or replace main battery and alternator cables. Inspect and clean engine and body grounds.
Big Three and all grounds except for back of block grounds cleaned and reattached. They don't come off when I pull them and no corrosion on the main to body.

When I move the box holding the pcm towards the body just a bit the gauge goes crazy and it even died once. When I let off, it goes back to normal. I pulled the pcm cover off and some of the wires have green corrosion in between them. In between the plastic over the wires?? I rerouted the cables that were hanging over it. Pulled the 7mm bolt out of the connectors and put them in nice and tight. No corrosion on the connectors. So, I'm not sure what I did to make it better really. No trouble since!.. then..

Today, it rained on my way home and the abs/brake light flashed off and on quickly, which is usually what happens first then the gauges and radio go off.

Is there a bare wire or wires that are missing the corrosion? It wouldn't just be in between the plastic if there wasn't metal somewhere would it? Corrosion could run down them from above?

I thought I had it beat for the last three days. Loving it. Kind of hurt a bit to see that light.
 
Last edited:

RET423

Full Access Member
Joined
Dec 4, 2017
Posts
134
Reaction score
156
I think your ABS/BRAKE light is a separate issue, when it rains it can wash brake dust onto the sensor and cause it to stop reading temporarily; have the rest of your gremlins stayed away since you tightened the harness and cleaned the grounds?
 

rockola1971

Full Access Member
Joined
Dec 29, 2016
Posts
2,643
Reaction score
3,598
Location
Indiana (formerly IL)
2 likely problems here affecting the cluster. First your "green corrosion" in between wires at the PCM. Obviously the wire insulation cant be doing that. The green corrosion is copper oxide and is essentially copper "rust". The green is leaching out of the wire at the terminal ends in the connector. You may need to replace the whole plug and the wire as much as 3 or 4 feet up the harness. Then the instrument clusters have a known issue called silver migration which is essentially silver "rust" on the back side of the cluster circuit board. The solder has silver in it. The board has to be cleaned with isopropyl alcohol and solder joints inspected for cracks and it doesnt hurt just to reflow ALL OF THEM. Clean the connector at the rear of the cluster too, the one on the cluster and the one on the firewall. Silver "rust" appears as a whitish to gray to dark black powdery substance. This is why very old silverware that is made of silver or thick layer plated gets jet black when its truly very old. Its just corrosion and can be cleaned (truly when silver is cleaned you are stripping the corrosion and a fine layer of silver off revealing non corroded silver underneath).
 

Forum statistics

Threads
132,771
Posts
1,873,985
Members
97,608
Latest member
Primetimetoons2
Top