No power when switch is on postion

[mojavemark]

Have a wierd one here. My 85 D 150 with a 318 just shut down on me while driving down the road, no warning, just shut down.
When the switch is in the on and run postion, I have no power to anything, turn signal, radio, wipers ect, except for the heater blower.
However in the acc postion everthing works. The thing will crank over just fine, but wont start.

I replaced the ignition switch with a new one, no change. I'm thinking a fusible link maybe. Does the switch get power from different wires in the on and acc. positions?

Also, the chilton shows only 5 wires to the switch, but there are 7. Can anyone clear this up for me? Thanks in advance. Mark

[76D100]

No power in run,
power in start but no spark?
power in acc?

Ballast resistor problem?
Check your fuses in your glove box.

[mojavemark]

Correct 76d, all fuses are good. First thing I check.

No matter what position the ignition switch is in, the only power at the starter relay is the red wire, I think that is the feed. No power out at all. Does any one know when the other wires should be hot, like only when cranking?

Some tests I did.
No volts to coil anytime.
12.6 at black wire to alternator at all times, 0 volts on other wires anytime.

Cant check voltage to ballast because no voltage out of starter relay. The best I can tell is that is where it gets it juice.

Any other suggestions?

[mojavemark]

Correction from above.

10.5 to 11 volts out of starter relay to ballast and coil, but still no start. Next check is for voltage to ignition module.

[76D100]

get a trouble light and start traceing from your battery to your ignition. It could take some time. Mine had a problem similar to this where the circut board in my dash fried at the amp meter. I jumped with a fuseable link untill i can swap the dashes from my parts truck.

You havent seen any smoke in your dash have you?

If need be you can probibaly jump power form your battery to your coil? and again start the truck by jumping your ignition on your fender.

[mojavemark]

No smoke from the dash, only from me trying to figure this out. ha ha.

When it shut down on me last night, 70 miles from no where, I tried hot feeding the coil, no start, no run.

I guess it is time run it down wire by wire.

I'm not real good at reading wiring diagrams, where does the on side of the ignition switch get its power, {which color wire**?

Any more suggestions are welcome, and thanks

[mojavemark]

Here is what I have so far.
Truck running good, then just up and shut down. Wont start.
No power when ignition switch is in on or run, but power in acc position. Engine will crank but not start.
11 volts when cranking at coil.
My ballast resistor is of the 2 connector type. 11 volts on one side, the one with two wires, and only about 1 volt on the other side when cranking.
Did the bypass on the ballast, truck almost starts, but not quit, but wires get kinda warm fast at the ballast and stater relay.

This all is telling me something, but I'm not sure quit what. Any Ideas?

[76D100]

go buy a new ballast, give it a shot.

[mojavemark]

UPDATE
Truck running good, then just up and shut down. Wont start.

No power when ignition switch is in on or run. No turn signals, radio, gauges or anything else that should work in the run and acc. position.
Engine will crank and start, but dies when key goes into run position. I can now hot wire the coil to get it to run.
When switch is in ACC. position, every thing works.

I get battery voltage every I should when cranking.

Chilton shows 5 wires to ignition switch, but there are 7. Anyone have a correct diagram for this, or a schematic of the ignition switch so I now what wires to trace down to find out why no power in the on position?

[mojavemark]

Finally found it!!!!!!!!!!

Fusable link was blown. Bad news is that it is the one where there is a 5 way splice/plug, it has 1 heavy gauge wire going in and 4 coming out. Its the one where 1 wire goes to the alternator, 1 to the amp gauge, 1 to the fuse panel and light switch, and 2 go to the ignition switch.

One of the two that go to the switch was blown, or burned, which ever you want to call it, and it is burned out clean in to the plug. NO way to splice a new fuse link in, not enough wire left.

Anyone ever have to replace this. I'm also wondering if you can safely replace the fuseable links with fuse holders and fuses?

[bherder]

Sounds like you've found the dreaded 5-way cluster-f**k under the dash. Another one of The Dodge Boys weak links.

Yes you can repair this, but you have to make it better than it was. I repaired/replaced mine ... Use wire gauge BIGGER than you think you'll need (I used 8 gauge wire) and do NOT run it through the bulkhead connector. To do it right, you'll need to SOLDER a new wire, separate wire, through a hole/grommet in the firewall going from your 'Point A' to your 'Point B' .... And yes, I used an inline fuse (Fusable link wire is just a cheap cost-cutting measure from the factory) .....

I think your big prob is going to be finding out exactly WHY it fried in the first place... Something caused it.... My first guess would be a faulty circuit going to/through the amp gauge... This is a REAL COMMON problem....

[mojavemark]

Thanks for info bherder. Knowing others have used fuses makes me feel better. I hate fusible links.

I guess I wasn't real clear on which splice {molded plug** though, its not under the dash, its in the engine compartment. It is the one where 2 of the wires coming out are fusible link, both orange, only about 4 or 5 inches worth, then go to the switch, one turning to dark blue, the other one pink. Only the fusible link was bad.

I have not found any problems with shorts in the system so I'm hoping it just got old and brittle from age and heat under the hood and finally gave out. It looks like I'm going to have to cut the molded plug out and re-splice this mess together. That is why I'm thinking a fuse block would be the way to go.

If any knows what the amp rating on these two circuits are let me know so I can properly fuse them.