No power until started
Thread Starter
|
6th Gear
Joined: Apr 2026
Posts: 6
Likes: 1
No power until started
Hey guys
bought this 84 351w 4x4 not running and got a lot of help from this forum through reading other people's posts
you guys helped me get the truck started and rolling
now I have a weird question
The truck has no power until the truck is actually started and running. the starter cranks fine and the truck starts and runs well, but if the truck it not running there is no power to any lights, radio, anything. I k ow that this must be short somewhere but if you guys had anywhere to look right off bat that would be great! Checked the fuses underneath the driver side dash but all was good. Has push start button i assume to bypass clutch saefty switch.Any advice would be appreciated! U guys are badass
bought this 84 351w 4x4 not running and got a lot of help from this forum through reading other people's posts
you guys helped me get the truck started and rolling
now I have a weird question
The truck has no power until the truck is actually started and running. the starter cranks fine and the truck starts and runs well, but if the truck it not running there is no power to any lights, radio, anything. I k ow that this must be short somewhere but if you guys had anywhere to look right off bat that would be great! Checked the fuses underneath the driver side dash but all was good. Has push start button i assume to bypass clutch saefty switch.Any advice would be appreciated! U guys are badass
FTE Legend
Joined: Nov 2015
Posts: 30,828
Likes: 4,094
From: Angier, NC
Welcome to FTE
That "push to start" has me thinking it is not for the clutch bypass as you dont get anything till running so it is like it is running off the power from the ALT.
Check under the dash by the clutch pedal to see if you see a safety switch. You are right at the year where I think they started to use them.
Then out at the starter solenoid on the big lug that the battery cable is on you should have 1 to 3 wires on it also.
Them wires are fuse links and I am thinking 1 or more are bad and not letting power to the inside of the truck.
You can use a test light and check each wire down where it connects to the main wire of the harness. If it lights up it is good.
They say you can pull in the wire at the main wire and if it stretches it could be bad. I have also tried to bend the wire and if it makes a sharp bend it could be bad but a test light is the best way to check.
Let us know what you find.
Dave ----
That "push to start" has me thinking it is not for the clutch bypass as you dont get anything till running so it is like it is running off the power from the ALT.
Check under the dash by the clutch pedal to see if you see a safety switch. You are right at the year where I think they started to use them.
Then out at the starter solenoid on the big lug that the battery cable is on you should have 1 to 3 wires on it also.
Them wires are fuse links and I am thinking 1 or more are bad and not letting power to the inside of the truck.
You can use a test light and check each wire down where it connects to the main wire of the harness. If it lights up it is good.
They say you can pull in the wire at the main wire and if it stretches it could be bad. I have also tried to bend the wire and if it makes a sharp bend it could be bad but a test light is the best way to check.
Let us know what you find.
Dave ----
Moderator
Joined: Jan 2001
Posts: 56,949
Likes: 2,718
From: Virginia
I am assuming you still have the keyswitch also? What happens if you turn the keyswitch without starting it, and slowly move the keyswitch through it's travel. Does the radio start playing at a certain spot? Does the radio start playing if you turn the keyswitch backwards to acc position?
Last edited by Franklin2; Apr 20, 2026 at 01:33 PM.
Thread Starter
|
6th Gear
Joined: Apr 2026
Posts: 6
Likes: 1
Welcome to FTE
That "push to start" has me thinking it is not for the clutch bypass as you dont get anything till running so it is like it is running off the power from the ALT.
Check under the dash by the clutch pedal to see if you see a safety switch. You are right at the year where I think they started to use them.
Then out at the starter solenoid on the big lug that the battery cable is on you should have 1 to 3 wires on it also.
Them wires are fuse links and I am thinking 1 or more are bad and not letting power to the inside of the truck.
You can use a test light and check each wire down where it connects to the main wire of the harness. If it lights up it is good.
They say you can pull in the wire at the main wire and if it stretches it could be bad. I have also tried to bend the wire and if it makes a sharp bend it could be bad but a test light is the best way to check.
Let us know what you find.
Dave ----
That "push to start" has me thinking it is not for the clutch bypass as you dont get anything till running so it is like it is running off the power from the ALT.
Check under the dash by the clutch pedal to see if you see a safety switch. You are right at the year where I think they started to use them.
Then out at the starter solenoid on the big lug that the battery cable is on you should have 1 to 3 wires on it also.
Them wires are fuse links and I am thinking 1 or more are bad and not letting power to the inside of the truck.
You can use a test light and check each wire down where it connects to the main wire of the harness. If it lights up it is good.
They say you can pull in the wire at the main wire and if it stretches it could be bad. I have also tried to bend the wire and if it makes a sharp bend it could be bad but a test light is the best way to check.
Let us know what you find.
Dave ----
Hey Dave sorry been busy week, you were correct, fusible link looks like bacon so that was the issue, thanks again. One more problem for someone with more knowledge than me, whenever the hazards or brights are turned on the truck dies, but will run the normal lights and blinkers just fine? Maybe just a bad ground somewhere? All lights on the truck work and if you are driving (past certain speed or rpm I guess) you can turn on brights but I feel like it starts to drain battery? Thanks for all the help again u guys are badass
Thread Starter
|
6th Gear
Joined: Apr 2026
Posts: 6
Likes: 1
I am assuming you still have the keyswitch also? What happens if you turn the keyswitch without starting it, and slowly move the keyswitch through it's travel. Does the radio start playing at a certain spot? Does the radio start playing if you turn the keyswitch backwards to acc position?
Yes still have keyswitch as well, no power at all while it travels through from off to on. Power only come to cab when truck is cranking, I believe Dave had the right idea but thank you for the input much appreciated. I have another issue I posted about in another reply with the brights, this trucks really making me work for it lol
FTE Legend
Joined: Nov 2015
Posts: 30,828
Likes: 4,094
From: Angier, NC
Hey Dave sorry been busy week, you were correct, fusible link looks like bacon so that was the issue, thanks again. One more problem for someone with more knowledge than me, whenever the hazards or brights are turned on the truck dies, but will run the normal lights and blinkers just fine? Maybe just a bad ground somewhere? All lights on the truck work and if you are driving (past certain speed or rpm I guess) you can turn on brights but I feel like it starts to drain battery? Thanks for all the help again u guys are badass
If so then try the head lights on high and 4 ways now does it still shut off?
I am thinking all os good now and here is why I think it was shutting down.
You were running off the ALT. as no power was feeding anything inside the truck because of the bad fuse link.
When you had the lights on it was pulling more power than the ALT could supply and the ICM did not have the power to keep spark going so motor stopped.
If you still have this problem then we will need to dig deeper.
I would also check what the ALT is putting out at idle with everything off just motor running.
Then bring up the RPM to say 2500 and what do you get for voltage at the battery?
Now turn on the head lights, heater blower on high and radio if you have one.
What do you get at idle for volts?
Bring the RPM up to 2500 what do you get for volts?
The ALT should put out between 13.5 to 14.5 volts. It may be lower at idle but with the RPM at 2500 the voltage should be in that range.
If not we will need to do a little more testing to find if the ALT or REG is bad.
Dave ----
Moderator
Joined: Jan 2001
Posts: 56,949
Likes: 2,718
From: Virginia
Make sure you have the important ground going from the back of the engine to the firewall. You may want to add a ground from the battery neg to the radiator support. Make sure you scrape the paint off before bolting it on.
Thread
Thread Starter
Forum
Replies
Last Post
