An Electrical Mystery??
Thread Starter
|
Senior User
Joined: Mar 2004
Posts: 111
Likes: 0
An Electrical Mystery??
I haven't had any problems with my truck's (66 Merc100) electrical system...until yesterday that is! 
I started her up and the headlights and tails came on fine...but the turn signals, heater, wipers would not work. Then...after about five minutes of idling they came back to life! I started her up today...and the same thing happened!
The only thing I've changed this week has been the addition of a washer pump...but I used the existing wiring. Could it be that I didn't ground the pump correctly?
If so, then why would everything come back to life after it's idled for a while?
Thanks for the help!
Chad
I started her up and the headlights and tails came on fine...but the turn signals, heater, wipers would not work. Then...after about five minutes of idling they came back to life! I started her up today...and the same thing happened!
The only thing I've changed this week has been the addition of a washer pump...but I used the existing wiring. Could it be that I didn't ground the pump correctly?
If so, then why would everything come back to life after it's idled for a while?
Thanks for the help!
Chad
Postmaster
Joined: Apr 2002
Posts: 3,613
Likes: 6
From: Coal country
I bet you disturbed some wiring or connectors in there.
Lights are on a separate circuit from the keyed ignition switch, but everything else you mentioned routes through the switch.
From the description, it sounds like you need to check the power supply wiring to the ignition switch wiring harness, and/or the fuse box.
It is usually easier to inspect the wiring with the gauges removed.
Lights are on a separate circuit from the keyed ignition switch, but everything else you mentioned routes through the switch.
From the description, it sounds like you need to check the power supply wiring to the ignition switch wiring harness, and/or the fuse box.
It is usually easier to inspect the wiring with the gauges removed.
Thread Starter
|
Senior User
Joined: Mar 2004
Posts: 111
Likes: 0
banjopicker66 (love that avatar!) I didn't go near the ignition, or any of the connectors under the dash....I actually used the wire from the previous pump.
Is it possible that I did not ground the pump and it's affecting the system...I attached the ground wire of the pump to the inside fender well.
Is it possible that I did not ground the pump and it's affecting the system...I attached the ground wire of the pump to the inside fender well.
New User
Joined: Apr 2004
Posts: 8
Likes: 0
you have a bad ground witch one i don't know but it is using your lighting ground as a sorce of ground, backfeeding, This can burn up wireing becareful, a lose connection can get hot and then work for awhile this is called arkwelding
Postmaster
Joined: Apr 2002
Posts: 3,613
Likes: 6
From: Coal country
Glad you like the avatar.
Rethinking your situation, I have to correct myself a bit. It looks like you are getting power TO the ignition switch - as indicated by the engine starting and runnning.
Looks like the other power feeds may be a problem. I would carefully go through the fuse box, check for loose fuses, rusted fuse contacts, loose wires, etc. If you have any circuit breakers, check them as well for continuity when cool.
I'll check my '66 for any more ideas.
Also, the earlier post about a bad ground is well made. I doubt that installing the ground for the pump did anything, though,
I still think you disturbed something in there, such as a ground about to go bad.
Rethinking your situation, I have to correct myself a bit. It looks like you are getting power TO the ignition switch - as indicated by the engine starting and runnning.
Looks like the other power feeds may be a problem. I would carefully go through the fuse box, check for loose fuses, rusted fuse contacts, loose wires, etc. If you have any circuit breakers, check them as well for continuity when cool.
I'll check my '66 for any more ideas.
Also, the earlier post about a bad ground is well made. I doubt that installing the ground for the pump did anything, though,
I still think you disturbed something in there, such as a ground about to go bad.
Thread
Thread Starter
Forum
Replies
Last Post
Y2KW57
1999 - 2003 7.3L Power Stroke Diesel
59
Jan 29, 2017 01:44 PM
ssummerangel3
1968-Present E-Series Van/Cutaway/Chassis
1
Jul 27, 2015 05:27 PM
ng19delta
1987 - 1996 F150 & Larger F-Series Trucks
17
Mar 30, 2015 10:27 PM
WBCody
1987 - 1996 F150 & Larger F-Series Trucks
9
Sep 1, 2010 10:30 AM
TheMonkey
1987 - 1996 F150 & Larger F-Series Trucks
11
Feb 4, 2009 06:04 AM
