It does sound like the ignition switch. Do other things not work when the tach doesn't? Like the turn signals and clock - if you have one?

 

Do the heater fan, radio, and any other key-on accessories work after jiggling the key but don't work prior to that? Might try just turning the key a bit towards yourself....

 

Alright to answer your questions,

As of late, like within the last few weeks, my heater fan has been turning on and off at very random times, thought it was a fuse but fuse is fine and so are the connectors in the engine bay. I dont know if that is related. The only other thing that I could say does not work when the tach doesnt is the fuel and temp gauges are lower than they should be, they go back up to where they should be and then go back down again at random times. I know this because I have been filling my truck up and I KNOW i have a full tank, and it says 3/4 tank, then as I am driving it may click back up to all the way full, and then down the road a bit go back to 3/4 tank, it does this at random times. I have read about jiggling the key and I havent had any luck with that. I do know for a fact though, my column is exposed because the gear selector wire snapped and is attached with a nut and screw, but you know that rod that goes down to the ignition switch? Well when I am driving and I dont even touch the key, and just pull up slightly on the rod the entire truck shuts off, and they key didnt move from its running position. I dont know if that information might help too.

 

Oh, and I forgot to mention that my radio does keep resetting at random times when I start the truck for some reason, not keeping its settings.

 

You may be experiencing multiple problems. The gauge problem may be the ICVR if the lower reading lasts for more than a few seconds. But if it is quick then you may be experiencing an ignition switch intermittent failure. The gauges are thermal so will continue to read for a while without power.

But most of the problems fit with an intermittent ignition switch. And that is a fairly cheap fix so I think I would start there.

 

Yes, I would investigate that famous pot-metal piece that connects the ignition switch to the key tumbler; certain versions of this are known to break after too many people try and pull themselves up into the truck via the steering wheel.

 

I have done some research and from what I have found is this piece.

More Information for DORMAN 83280

It says with tilt wheel though, and I do not have a tilt wheel and I cannot find any information if it matters or not.

I have not taken the steering column apart yet, but on rock auto I can order everything I need to replace the old parts for $30, which seems worth it to replace with parts I know work.

 

Oh, and I forgot to mention the truck is in the shop now to completely fix the charging system. Apparently my charging system was shot only making 12.6 volts under full load, and only making 13.2 volts while in drive, only making 14.5 while in park. We will see how this affects my problems once it is fixed.

 

Are you sure you don't have a tilt wheel? Many do and don't know it. The turn signal lever pushes forward to tilt the wheel, and the cutout for the lever is a T rather than just a slot. If not a tilt column that part won't work.

 

Yeah, I am 100% positive I do not have a tilt wheel. Where would I find the piece for the column for a non tilt wheel?

 

The two columns are completely different internally and there isn't a similar piece on the fixed column. So there's really nothing of that sort to break. However, the tumbler where the key goes in can wear out and cause the rod going to the switch to move less than it is supposed to move. You can adjust the switch's position to some extent, but if the tumbler is failing that may be part of the problem.

 

Ah, ok. That makes sense, my ignition lock cylinder is very loose, like I have to wiggle it sometimes just to get the key in and can sometimes get the key in with the lock cylinder too far forward and it jams. I am going to say I need to replace the lock cylinder for sure. Maybe the ignition switch too?

 

Start with the cylinder and then do the ignition switch if needed. They are separate enough that it is as easy to do them in two steps as one.

 

I am waiting for my ignition tumbler to come in the mail and I was reading over this thread again, and remembered the mentioning of replacing the ICVR. Since I got the trucks electrical fixed, even so, with a 75amp alternator I only pull 13.5v with full load, (blower, headlights, radio, turn signal, wipers) **speaking of which, my headlights drop the voltage a good 1v, from 14.5 to 13.5, is this normal? could the ground for the headlights be the cause?** so would the ICVR in my truck be fine and just the input voltage is incorrect? Would replacing the ICVR like you did help this issue? my gauges now read correct sometimes, as in a full tank, but they seem to go back and forth, I am interested in replacing it if it will help.

If you cannot tell, I despise dead or incorrect reading gauges in the dash.

As for the tach it is STILL intermittent coming and going whenever it pleases, when I am driving it may come on for a couple blocks and then go out again, some days it will stay on all day, clicking on at startup and turning off with the truck, but then when I let the truck sit for a couple hours the tach will not work for maybe 10 minutes then spring back to live while I am driving, or sometimes not, its like it has a mind of its own, haha.

 

The input voltage to the ICVR makes effectively no difference to it as it is governed by load.

And the voltage drop to the headlights is due to the very long and small wiring from the battery, into the cab, through the fuse box, through the switch, and then back to each headlight. The little volts get lost along the way. That can be fixed by installing a headlight relay kit, which uses the above-mentioned little wiring to pull in relays which are fed with heavy wiring. Do a search in the forum for "headlight relay" or check LMC or another supplier.
If the gauges are changing when they shouldn't then you need a new, better ICVR.