No power to fuel pump or lights

audiobox · 01-24-2008, 07:17 PM

Symptoms:
1990 Burb with newish crate engine cranks, but no power to fuel pump, lights, heater fan, etc.

Background:
This happened last winter too. The lead-up was the same... towed the trailer back from camping in the rain and Burb sits in the parking garage for a month. A few weeks of night time temps in the mid-twenties and now, Burb will crank, but no juice to the fuel pump, lights, heater fan = no start.

This happened last Winter and I had it towed to a shop. Mechanic said he messed with the harness some and, "I don't know what did it, but it's runnin' now." OK. 300 bux.

Now it's in a part of the underground garage with 9' of clearance, so I don't know if I can even get a tow out of there.

I turned the lights on and futzed with the harness where it passes over the valve cover on the battery side of the compartment, but no lights, no joy.

Any ideas or suggestions for getting the beast fired up?

75K30 · 01-24-2008, 08:15 PM

Welcome to the site:
The mechanic that was fussiing around with the harness, did he remove the bulkead connection at the firewall?
I would check grounds, and battery cables firts to make sure all connections are good, this includes fusable links etc, etc.
Then I would check the main harness that enters the cab via the firewall. I have seen the connections develop some corrossion and fail. The harness and connector was good, but the connections inside were dirty. Would actually see shut off while driving.
The final thing that comes to mond is the actual ignition switch itself. If you move the switch around, can you make the lights come back to life?
There is an electrical switch in the column with some rods that can wear, and cause some issues, especially if you have a tilt wheel.

audiobox · 01-24-2008, 08:52 PM

Quote:

Originally Posted by 75K30

Welcome to the site:
The mechanic that was fussiing around with the harness, did he remove the bulkead connection at the firewall?
I would check grounds, and battery cables firts to make sure all connections are good, this includes fusable links etc, etc.
Then I would check the main harness that enters the cab via the firewall. I have seen the connections develop some corrossion and fail. The harness and connector was good, but the connections inside were dirty. Would actually see shut off while driving.
The final thing that comes to mond is the actual ignition switch itself. If you move the switch around, can you make the lights come back to life?
There is an electrical switch in the column with some rods that can wear, and cause some issues, especially if you have a tilt wheel.

Thanks for the welcome and reply!

"did he remove the bulkead connection at the firewall?"
I don't think so. He wasn't specific about what he did and, as I said, he didn't really know what popped things back on, but he did mention messing with the section of the harness that crosses the manifold, as he thought there might have been some melting there.

"The harness and connector was good, but the connections inside were dirty."
You mean the various snap-lock connectors?

"If you move the switch around, can you make the lights come back to life?"
Nope. I tried that.

"There is an electrical switch in the column with some rods that can wear, and cause some issues, especially if you have a tilt wheel."
So, is power routed through the switch so that you can crank the starter, but not have power to the lights and fuel pump? That's is the situation I have.

Someone suggested that there might be a problem between the battery and the aux power terminal in the fuse panel. If that sounds reasonable, could I run a temporary jump wire from the battery to the aux term at the fuse panel and get an emergency start and drive to a garage?

75K30 · 01-24-2008, 09:12 PM

yes, I was refering to the snap type connectors. I had a burb with a similar problem that came in, and I could wiggle the connections and it would come alive. Was able to narrow it down to a connector under the steering column. Obviously the connector was in the engine side and accessing it was a bear, but hey, I found it and it turned out to be a single connection inside of the plug itself. This was an 86 burb, and i fixed it a few years ago, and the problem has not returned. Worth a look.

The last statement is probably the most reasonable solution to your problem. In my first reply, I mentioned all connections and fusable links. This is always a safe place to start. Electrical problems can really be a pain to troubleshoot simply because of most connector locations. Kinda difficult to gain access to.
You know some of this can probably be verified with a cheap meter, and a decent set of electrical drawings. Can you read a schematic? This would be very helpfull. Might be able to determine where the voltage is missing, and narrow down your problem.

audiobox · 01-24-2008, 09:43 PM

Quote:

Originally Posted by 75K30

yes, I was refering to the snap type connectors. I had a burb with a similar problem that came in, and I could wiggle the connections and it would come alive. Was able to narrow it down to a connector under the steering column. Obviously the connector was in the engine side and accessing it was a bear, but hey, I found it and it turned out to be a single connection inside of the plug itself. This was an 86 burb, and i fixed it a few years ago, and the problem has not returned. Worth a look.

The last statement is probably the most reasonable solution to your problem. In my first reply, I mentioned all connections and fusable links. This is always a safe place to start. Electrical problems can really be a pain to troubleshoot simply because of most connector locations. Kinda difficult to gain access to.
You know some of this can probably be verified with a cheap meter, and a decent set of electrical drawings. Can you read a schematic? This would be very helpfull. Might be able to determine where the voltage is missing, and narrow down your problem.

"Electrical problems can really be a pain to troubleshoot simply because of most connector locations. Kinda difficult to gain access to."
Boy, no kidding. The Burb is parked with its nose touching the wall too. Makes me nostalgic for those cars back in the day that had all that elbow room around the engine.

"Can you read a schematic?"
Sadly, no. But I do have a VOM, so I'll start at the battery and work my way toward the engine compartment fuse panel. Might as well unsnap and clean those connectors as I go. First, I'll switch the lights on and flex every connector I can get to and see if they turn on. I won't be able to hear the fuel pump in the parking garage.

Thanks a lot for your suggestions!

75K30 · 01-24-2008, 09:50 PM

Well it does sound like you are on the right track, and you know it probably is not going to be easy, but we will keep our fingers crossed right? Lol.
Lots of luck, I hope it works out, and we all hope to hear back when you find the problem. We would like to learn from this. Might turn out to be something that we could refer to if this comes up again.

75

audiobox · 01-25-2008, 05:21 AM

Quote:

Originally Posted by 75K30

Well it does sound like you are on the right track, and you know it probably is not going to be easy, but we will keep our fingers crossed right? Lol.
Lots of luck, I hope it works out, and we all hope to hear back when you find the problem. We would like to learn from this. Might turn out to be something that we could refer to if this comes up again.

75

Your suggestions based on experience are worth a lot. I'll post back with my results. I need the Burb to run in the next four days, so I sure hope I can track this down. Thanks again!

Dragonfly · 01-25-2008, 10:43 AM

Check the fusible link by the starter. It is usually the smaller red wire coming from the wiring harness to the starter. It is a "fusible link" meaning it is usually very pliable (not quite like other wire) and it burns itself up if overloaded. If it burned itself up (blew) it breaks contact and you will not have power to your starter or anything inside the truck. I can't remember 100% for sure but I think it may effect the headlights.

At any rate, when you find the fusible link it will only be several inches long and should have a darker hard band (heatshrink) around it where it is spliced into the regular wire. If it is blown or burnt up it will either be very discolored or completely apart and seperated.
If this is the case get a new fusible link/wire the same size from your local parts store and splice it together again (don't forget the heatshrink to protect the splice) and re-connect it to your starter. It is a little more expensive than regular wire but it won't break the bank. DO NOT USE REGULAR WIRE OR YOU MAY TURN THE BURB INTO A MOBILE BBQ!!!! If you use regular wire, whatever is causing your overload and blowing the fusible link could start a wire harness fire.

audiobox · 01-25-2008, 11:03 AM

Quote:

Originally Posted by Dragonfly

Check the fusible link by the starter. It is usually the smaller red wire coming from the wiring harness to the starter. It is a "fusible link" meaning it is usually very pliable (not quite like other wire) and it burns itself up if overloaded. If it burned itself up (blew) it breaks contact and you will not have power to your starter or anything inside the truck. I can't remember 100% for sure but I think it may effect the headlights.

At any rate, when you find the fusible link it will only be several inches long and should have a darker hard band (heatshrink) around it where it is spliced into the regular wire. If it is blown or burnt up it will either be very discolored or completely apart and seperated.
If this is the case get a new fusible link/wire the same size from your local parts store and splice it together again (don't forget the heatshrink to protect the splice) and re-connect it to your starter. It is a little more expensive than regular wire but it won't break the bank. DO NOT USE REGULAR WIRE OR YOU MAY TURN THE BURB INTO A MOBILE BBQ!!!! If you use regular wire, whatever is causing your overload and blowing the fusible link could start a wire harness fire.

Thanks for the suggestion. I will check this out, since I'll be getting up close and personal with the wiring harness today. However, as I noted in my original post, "engine cranks, but no power to lights or fuel pump..." So, if the fusable link is a direct wire to the starter, it's probably ok, since the starter does crank.

crabtruck · 01-25-2008, 01:53 PM

Welcome to the forum audiobox.
I'm thinking 75 is probably right on with the idea that you have a bad connection somewhere, not a bad part.
No power to fuel pump and heater would lead me back to key,
but no power to lights makes me think the problem is even more basic.

With the key on, probe the fuses for voltage, noting which does NOT have it.
Should quickly guide you to the right place.
If you have a schemtic for that truck you want help reading,
post it and a number of us could help.

BTW if your "name" is related to mods you've made to the truck,
do a careful inspection of the areas around your hookups.
Sometimes mods get loose or cause other problems.
Good luck, electrical is not hard, just annoying at times.

01-24-2008, 07:17 PM	#1
audiobox Full Member Join Date: Jan 2008 Location: Portland, OR Posts: 10	No power to fuel pump or lights Symptoms: 1990 Burb with newish crate engine cranks, but no power to fuel pump, lights, heater fan, etc. Background: This happened last winter too. The lead-up was the same... towed the trailer back from camping in the rain and Burb sits in the parking garage for a month. A few weeks of night time temps in the mid-twenties and now, Burb will crank, but no juice to the fuel pump, lights, heater fan = no start. This happened last Winter and I had it towed to a shop. Mechanic said he messed with the harness some and, "I don't know what did it, but it's runnin' now." OK. 300 bux. Now it's in a part of the underground garage with 9' of clearance, so I don't know if I can even get a tow out of there. I turned the lights on and futzed with the harness where it passes over the valve cover on the battery side of the compartment, but no lights, no joy. Any ideas or suggestions for getting the beast fired up?

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01-24-2008, 08:15 PM	#2
75K30 Senior Member Join Date: Jul 2006 Posts: 3,312	Welcome to the site: The mechanic that was fussiing around with the harness, did he remove the bulkead connection at the firewall? I would check grounds, and battery cables firts to make sure all connections are good, this includes fusable links etc, etc. Then I would check the main harness that enters the cab via the firewall. I have seen the connections develop some corrossion and fail. The harness and connector was good, but the connections inside were dirty. Would actually see shut off while driving. The final thing that comes to mond is the actual ignition switch itself. If you move the switch around, can you make the lights come back to life? There is an electrical switch in the column with some rods that can wear, and cause some issues, especially if you have a tilt wheel.

01-24-2008, 09:12 PM	#4
75K30 Senior Member Join Date: Jul 2006 Posts: 3,312	yes, I was refering to the snap type connectors. I had a burb with a similar problem that came in, and I could wiggle the connections and it would come alive. Was able to narrow it down to a connector under the steering column. Obviously the connector was in the engine side and accessing it was a bear, but hey, I found it and it turned out to be a single connection inside of the plug itself. This was an 86 burb, and i fixed it a few years ago, and the problem has not returned. Worth a look. The last statement is probably the most reasonable solution to your problem. In my first reply, I mentioned all connections and fusable links. This is always a safe place to start. Electrical problems can really be a pain to troubleshoot simply because of most connector locations. Kinda difficult to gain access to. You know some of this can probably be verified with a cheap meter, and a decent set of electrical drawings. Can you read a schematic? This would be very helpfull. Might be able to determine where the voltage is missing, and narrow down your problem.

01-24-2008, 09:50 PM	#6
75K30 Senior Member Join Date: Jul 2006 Posts: 3,312	Well it does sound like you are on the right track, and you know it probably is not going to be easy, but we will keep our fingers crossed right? Lol. Lots of luck, I hope it works out, and we all hope to hear back when you find the problem. We would like to learn from this. Might turn out to be something that we could refer to if this comes up again. 75

01-25-2008, 10:43 AM	#8
Dragonfly Full Member Join Date: Jan 2008 Posts: 19	Check the fusible link by the starter. It is usually the smaller red wire coming from the wiring harness to the starter. It is a "fusible link" meaning it is usually very pliable (not quite like other wire) and it burns itself up if overloaded. If it burned itself up (blew) it breaks contact and you will not have power to your starter or anything inside the truck. I can't remember 100% for sure but I think it may effect the headlights. At any rate, when you find the fusible link it will only be several inches long and should have a darker hard band (heatshrink) around it where it is spliced into the regular wire. If it is blown or burnt up it will either be very discolored or completely apart and seperated. If this is the case get a new fusible link/wire the same size from your local parts store and splice it together again (don't forget the heatshrink to protect the splice) and re-connect it to your starter. It is a little more expensive than regular wire but it won't break the bank. DO NOT USE REGULAR WIRE OR YOU MAY TURN THE BURB INTO A MOBILE BBQ!!!! If you use regular wire, whatever is causing your overload and blowing the fusible link could start a wire harness fire.

01-25-2008, 01:53 PM	#10
crabtruck Senior Member Join Date: Jul 2007 Posts: 4,121	Welcome to the forum audiobox. I'm thinking 75 is probably right on with the idea that you have a bad connection somewhere, not a bad part. No power to fuel pump and heater would lead me back to key, but no power to lights makes me think the problem is even more basic. With the key on, probe the fuses for voltage, noting which does NOT have it. Should quickly guide you to the right place. If you have a schemtic for that truck you want help reading, post it and a number of us could help. BTW if your "name" is related to mods you've made to the truck, do a careful inspection of the areas around your hookups. Sometimes mods get loose or cause other problems. Good luck, electrical is not hard, just annoying at times.