just picked up a 1976 D150 and I’m having a no-crank, no-start issue. I’m not really familiar with trucks this old. I also have a 1998 4x4 with the 5.9 Magnum, but this ‘76 looks like it has a bunch of custom wiring.



I was told it runs, but it’s been sitting for a while. The engine spins freely, the oil is black but not low, and the radiator is full of coolant. I hooked up a good battery, but when I turn the key literally nothing happens — no lights, no crank, nothing. The wiring in the engine bay around the ignition and electrical harness definitely needs attention.



Any help would be appreciated.

 

Recheck your battery connections, those fellers look pretty cruddy.

 

looking at ur pictures it looks as if some one has wired up a push button or some thing as there are sevral exstra wires on relay possibly broken yellow wire went to battery
possitive cable usualy conects were that yellow wire is connected

 

You definitely need to clean the wiring up a bit. Especially check the ends of the cables away from the battery. The hot cable to the starter as well as the ground cable. I've seen ground cables so corroded that they melt when you try to start the car. Also check with a volt/ohm meter to see if you're getting power to and from the ballast resistor. It's that white porcelain thingie (<---------fancy technical term) on the firewall. Those were a major bug a boo back in the day. I always carried a spare wrapped in a towel in case it failed on the road.

Since it's been sitting so long, I'd change the oil and filter. Get some fresh stuff in there so when you crank it, you're putting fresh oil through the engine. That way, when it DOES fire, it's got fresh oil in the bearings. It's won't correct previous wear but will minimize new wear from sitting. I'd also disconnect the fuel line at the pump and run a hose from a fuel can or small portable tank so you don't slurp garbage out of the old tank. Keep in mind, ethanol fuel is rough on the diaphragms in older fuel pumps.

 

How long is a while? You definitely need to over that wiring. Butt connectors don't belong on vehicles.

 

You are going to need to diagnose the system. This truck isn't a lot different than your 98 and basic principles apply. Do you have a power probe? If not you need one or a copy of one (Amazon, Harbor Freight, etc.), this will make your life much easier as it will allow you to check circuits for ground or power. Turning the key and not getting a response can mean a variety of things (no power to the switch, no power to the fuse block, no power to the bulk head fitting, etc.) but with a tester (power probe or test light) you will be able to trace the power from the battery to inside the rig and figure out where it stops.

Also you need to probe the starter to see if there is power there. You can jump the starter relay (located on the inner fender) to see if the starter will activate or not. If it does then you know you have power to that.

Just a guess here but either you have some wiring disconnected/broken or perhaps you have a burnt fusible link. You REALLY need a wiring diagram to help you understand what goes where and what is supposed to be connected. Electrical issues always seem magical and a mystery but in reality they are all just circuits, they need power and a ground (in and out). You just need to determine how the circuit is activated (most are positively switched whereas some like a dome light are negatively switched).

Yes your wiring looks messy, however it is near impossible to diagnose an electrical problem via pictures unless of course its something glaring like a wire or cable is disconnected.

 

Hey, I know it’s been a while, but I finally had time to work on it today. I replaced the battery connections and got some results, but there are still no lights or anything inside. I did get a click from the starter relay, and the engine attempted to turn over, but it was extremely slow and intermittent.

So I removed the starter and bench-tested it — it’s bad. It kicks out but barely turns. I installed a known good starter, and it turned over fine, but then everything went back to nothing again.

I now realize there was a lot of custom wiring done previously. I’m wondering if there are any rewire kits available for this model. I’d rather just go through and redo all the starter and ignition wiring so I know the problems are actually fixed.

For reference, I just installed the following new parts today:

• New ignition module
  
• New voltage regulator
  
• New ballast resistor
  
• New starter
  

 

I’ll probably come back next weekend. I’m going to pick up a Power Probe and a voltmeter in the meantime and go over the wiring diagram. Once I trace everything out and see what I find, I’ll let you know.

 

Check the continuity on your grounds. Your negative might look good at the battery but be corroded at the other end. This would reduce current flow below what is needed.

 

agreed, grounds are the most commonly over looked and under maintained part of the electrical and can cause major headache.

Not sure how factory you want it to be, I would opt for a push button, switch battery-switch-starter, at least for the short term, one less issue to fight checking out everything else, obviously a wire on a toggle straight to the coil should give you spark as well

does it have lean burn? that's another headache you can chuck in the dumpster