Dash ground problem ?

[ruger444]

1998 chevy tracker,116.000 miles 1.6 4x4. Low voltage to high beam lights, 5.4 volts.Also 4x4 lite blinks when I hit a bump.The hi beam indicator lite is always on when lites are on.And overdrive kicks in and out when I hit a bump.I added a ground cable to tranny and frame and also to battery and frame. also cleaned all ground connections under hood. Am I missing a important ground someplace? Any help would be greatly appreciated !

[dbacon]

I had a problem with the OD kicking in and out. Since OD is 4th gear, and the TCC is locked up, it is rather violent. I traced this to wires between the shifter-mounted OD switch and the TCM. I cut them loose and ran a new pair of wires directly from the shifter-mounted switch to the TCM, where one is signal, the other is ground.

The switch simply closes between those wires to turn OFF OD. You could cut the OD switch input wire at the TCM to see if it is in the field wiring. Mine would get wet and probably shorted to ground, because I have a dash/firewall rain leak that I haven't cured yet.

This is all in case it isn't related to the other problems you described.

[ruger444]

traced all wires from that switch and are all ok. od lite and switch works fine when in od.

[dbacon]

That's good, so probably you have to trace where the voltage loss is, and I agree, it could be a ground problem.
On my Sidekick, the headlights get power directly, and a relay pulls the common terminal to ground, so you could start there, with a long wire between battery negative and your VOM. If the relay doesn't have "0" on its grounded pin, it would give you a good place to attack.

I hope you have good schematics, you might find jtgh to help, he is extremely generous with his library and vast knowledge. He maintains a very helpful web page also. But I would wait for him to notice your post, I would't bother him directly, unless he invites it, he has got to be the busiest man on this forum... Great guy!

[jtgh]

Electrical power failure


a vm and 5mins, your answer. vm = voltmeter, any.

Low voltage to high beam lights, 5.4 volts

fix this FIRST, never accept low power to the HL , it runs off the MAIN power feed.
if the main power feed is bad, nothing else will work, nothing.

check the main feed.

[jtgh]

the 98 is a little more complex than my page, but the primary checks are the same.

do you have DRL , HL?

here is 98 AT schematic.

see HL and distra shematics , 98 below.

easy problem tell me what voltage you have on the main feed.

HL on , HIGH beam, meter toughing (black test lead) to ground on body
and then same test black lead on minus post of battery actual.

this will cut problem in half. or better.

[ruger444]

will check when I get home LOL scanner says power loss backup.

[jtgh]

scanner didnt lie , you lost power to the Memory power pin on the ECU.
the ecu has a special memory , one that is volatile, and is connected to HOT AT ALL TIMES FEED ( i can it the main battery feed buss) (making it Non volatile in practice)

remember there are 2 paths for electric flow.
power and ground.

assume it can be either and never guess wrong.

to do that ,always take 2 readings. (voltage tests)
one with meter ground on body, and then repeat with meter on battery minus post.

short cut:
if minus post was just cleaned (under and inside) [ of course you did that 1st thing and checked fuses]
then you can put meter to the bolt of the terminal clamp.
repeat the tests.



if the values are more than 1/2 volt diff. your grounds are SNAFU'd ..

cheers.

[ruger444]

Thanks for the help !!! Found corrosion on main power bus connector. All problems now fixed!!!

[jtgh]

cooooooolllllllllllllll


i hope you found it straight away.

was it on top or bottom. I hear that water and salt can go up the front right strut tower and splash the bottom of the fuse box there.
is that what you found.

we get a lot of these.