Replace idiot lights with gauges.

[75gmck25]

How comfortable are you with simple troubleshooting of wiring? Some guys who have the skills to rebuild an engine or transmission could not find a short in the wiring or bad connector if someone helped and spray painted it orange for them.

If you find a junkyard cluster from the same vintage, in good condition, the swap should be easy. You swap the cluster, swap the oil and temp senders, and it should work. In general, your truck was factory pre-wired for both gauge and non-gauge options.
- clusters can be grouped by years and you need the right group. For example, my ‘75 has a mechanical oil pressure and an ammeter. Later gauges had electrical oil and voltage gauges. I’m not sure of the range that would match your truck.
- sending units in the 70’s changed in the resistance “profile” over the years. If you get the wrong one it will work but your gauge will be consistently high or low. It took me 3 tries to get one that shows about 3/8 scale at about 190 degrees, because the original OEM ‘75 sensor from GM is no longer stocked in most stores.
- the old cluster plastic is brittle and may have been manhandled by the PO. Cracked mounting tabs and other issues are common.

 

[imjohnny]

Nothing left here now, use to be there was a wrecking yard near every small town in the area. Not no more!

I wish i had yards

We have a a great yard in town. They have an early 70s C10 coming in this week. Can’t wait to go attack it.

How comfortable are you with simple troubleshooting of wiring? Some guys who have the skills to rebuild an engine or transmission could not find a short in the wiring or bad connector if someone helped and spray painted it orange for them.

If you find a junkyard cluster from the same vintage, in good condition, the swap should be easy. You swap the cluster, swap the oil and temp senders, and it should work. In general, your truck was factory pre-wired for both gauge and non-gauge options.
- clusters can be grouped by years and you need the right group. For example, my ‘75 has a mechanical oil pressure and an ammeter. Later gauges had electrical oil and voltage gauges. I’m not sure of the range that would match your truck.
- sending units in the 70’s changed in the resistance “profile” over the years. If you get the wrong one it will work but your gauge will be consistently high or low. It took me 3 tries to get one that shows about 3/8 scale at about 190 degrees, because the original OEM ‘75 sensor from GM is no longer stocked in most stores.
- the old cluster plastic is brittle and may have been manhandled by the PO. Cracked mounting tabs and other issues are common.

Super comfortable with the wiring. Have done a lot of it over the years. Seems pretty straight forward as I research it. I am gonna keep looking at my local yards till I find one that works and try that I think. As for broken tabs....I got a nifty plastic welding set up for Christmas this year.....so it would give me a chance to try it out. Haha.

 

[82sbshortbed]

None of my gages worked so I went and got a temp and oil pressure gages. Super easy to install. You can get 2 inch ones that fit in the spots of the lights. I put my temperature where the clock was and the oil at bottom of dash by the pb release. I'm sure you can do a better job than my quick one but they work just fine. Also put a tachometer on the colum. They were cheap too.

 

[Craig 85]

I had an '80 C20 3+3 with idiot lights. I was able to fit some Autometer/Autogauge mechanical gauges into the factory idiot light locations. Sorry I don't have any pictures, this was 1995. From my recollection I just pulled back the circuit to clear the gauges. I trimmed the back of the bezel and probably the light pockets so the gauges fit flush. It's possible I had to drill the backs open a little more for wiring.

I know on at least one gauge I had to wrap electrical tape around the gauge body to snug up the fit in the factory light pod. The gauges are have white numbers, but I colored/tinted the bulb with Testors transparent green paint to better match the factory colors.

I'm pretty sure this is the kit I used. Auto Meter Auto Gauge #2348 2 1/16" dia. They are about $63.

You must be registered for see images attach

 

[imjohnny]

I had an '80 C20 3+3 with idiot lights. I was able to fit some Autometer/Autogauge mechanical gauges into the factory idiot light locations. Sorry I don't have any pictures, this was 1995. From my recollection I just pulled back the circuit to clear the gauges. I trimmed the back of the bezel and probably the light pockets so the gauges fit flush. It's possible I had to drill the backs open a little more for wiring.

I know on at least one gauge I had to wrap electrical tape around the gauge body to snug up the fit in the factory light pod. The gauges are have white numbers, but I colored/tinted the bulb with Testors transparent green paint to better match the factory colors.

I'm pretty sure this is the kit I used. Auto Meter Auto Gauge #2348 2 1/16" dia. They are about $63.

You must be registered for see images attach

Those are nice looking gauges.

 

[75gmck25]

You can buy individudaul replacement gauges from LMC. But they would be pricey if you bought a entire set.

I followed instructions I found online and replaced my ammeter gauge with a voltage gauge. The original ammeter uses the truck wiring loom as a shunt and the old wiring no longer has the correct resistance, or the small barrel fuses under the hood (2) have blown.

 

[SirRobyn0]

Obviously this is not my truck but I'm going to interject my personal opinion and Johnny can think about it. I fully understand that opening up the instrument cluster, removing the idiot lights and installing aftermarket gauges is likely the most economical choice, but to me I've always felt that they look a little out of place. I've seen installation where it looked like the install just went at the dash from the outside with a hole saw and tossed the gauges in and it was all hacked up. And I've seen installations where guys went in and carefully installed the aftermarket gauges into the cluster in such a way that they were recessed in like the factory gauges, obviously those installations look a LOT better, but to me they look out of place compared to factory gauges. With that said if I had a truck with idiot lights, and getting a used cluster I don't think is practical for me, if I couldn't afford to by repos then yea I'd find aftermarket gauges I liked and install them as carefully as possible.

Those are just my thoughts not trying to tell anyone what to do.

 

[imjohnny]

Obviously this is not my truck but I'm going to interject my personal opinion and Johnny can think about it. I fully understand that opening up the instrument cluster, removing the idiot lights and installing aftermarket gauges is likely the most economical choice, but to me I've always felt that they look a little out of place. I've seen installation where it looked like the install just went at the dash from the outside with a hole saw and tossed the gauges in and it was all hacked up. And I've seen installations where guys went in and carefully installed the aftermarket gauges into the cluster in such a way that they were recessed in like the factory gauges, obviously those installations look a LOT better, but to me they look out of place compared to factory gauges. With that said if I had a truck with idiot lights, and getting a used cluster I don't think is practical for me, if I couldn't afford to by repos then yea I'd find aftermarket gauges I liked and install them as carefully as possible.

Those are just my thoughts not trying to tell anyone what to do.

Yeah, I think I have decided to live with what I have for a bit and keep a look out for what I want. At some point I'll be able to find it without spending ALL the money. Haha.

 

[SirRobyn0]

Yeah, I think I have decided to live with what I have for a bit and keep a look out for what I want. At some point I'll be able to find it without spending ALL the money. Haha.

Sorry was out of town over the weekend and offline.

Yea, I know what you mean. Took me 3 or 4 years to find a pair of used running boards for my truck at a reasonable price (both purchase and shipping). Part of the problem there was I wanted old fashion running boards, not something modern.

 

[imjohnny]

So I have the truck home and am loving it. I do really want the gauges. The truck is a 77, and I picked up a very clean/working 76 cluster that has oil pressure, volts, and temp in it. I have done a ton of looking on here and elsewhere and am finding that different eras of these truck would be wired different ways, and I am wondering if there is anyone that knows what I am going to need. I am assuming a couple new senders for oil and temp, and probably a change in wiring for the volts, but other than those guesses, I am unsure. Want to do it right and know that this isn't completely plug and play, but from what I am reading, it shouldn't be too difficult. I like wiring and electric stuff, just need to know what senders I need and if I am gonna need to repin anything, and what to wire where and I can get it done. Appreciate any of you electric gurus that could help me out!

 

[75gmck25]

The original oil pressure gauge in a ‘77 was probably electric. Is the oil pressure gauge in the ‘76 cluster electric or mechanical (mechanical would have a fitting on the back for a hard line)?

If they both were wired for electric gauges it may be plug and play. You would need sending units for oil pressure and temp, but all the wiring should be there.

Sometimes the oil pressure sending unit has two terminals and one is for the electric choke. It cuts power to the choke if the engine is not running.

 

[imjohnny]

The original oil pressure gauge in a ‘77 was probably electric. Is the oil pressure gauge in the ‘76 cluster electric or mechanical (mechanical would have a fitting on the back for a hard line)?

If they both were wired for electric gauges it may be plug and play. You would need sending units for oil pressure and temp, but all the wiring should be there.

Sometimes the oil pressure sending unit has two terminals and one is for the electric choke. It cuts power to the choke if the engine is not running.

76 is electric. Mine only has the light, not a gauge. So you are saying it is prewired for the gauge, just wasn't installed in mine. Just need to add a second sending unit to the oil pressure and temp and that should be it?

 

[Ricko1966]

You should have a separate block mounted op switch for the choke and you will need a ps154 oil pressure sender for the gauge.

 

[imjohnny]

You should have a separate block mounted op switch for the choke and you will need a ps154 oil pressure sender for the gauge.

Do I need an adapter to keep the old oil sender in place and add this one to it?

 

[Ricko1966]

You replace the oil pressure switch behind the distributor with the ps154,leave the switch on the block alone.