Author Topic: Idiot Lights vs. Gauges in Dash  (Read 303 times)

Offline lumartin1989

  • Newbie
  • Posts: 10
  • Newbie
Idiot Lights vs. Gauges in Dash
« on: April 30, 2018, 12:41:58 PM »
Hi there,

I have a 1986 chevy K10. Currently the gauge cluster has idiot lights for the oil pressure, battery voltmeter, and temperature gauge. I want to replace these with gauges. I picked up a gauge cluster that has the gauges for all three of these at a junkyard last week, same year truck.

So I was hoping to change out the gauge cluster with the one I got at the junkyard. My question is do I have to have new sensors, etc... that will give the gauges a correct reading since they were operating the idiot lights in the original cluster? For example, if the sensor for the engine temperature in engine block (not sure where it is exactly), was meant to only read for the idiot light and will not work for a temperature gauge, I would need to replace that sensor in the engine? Same thing for the oil pressure?

Not sure if there is a write up anywhere for this anywhere on the forums, I did an initial search and couldn't really find anything.

Thanks in advance for the help!



Online zieg85

  • Carl
  • Site Supporters
  • Senior Member
  • ******
  • Posts: 6771
    • 73-87 GM squarebody extended cab and conversions up to 91 R/V series
Re: Idiot Lights vs. Gauges in Dash
« Reply #1 on: April 30, 2018, 01:53:06 PM »
It is not a plug and play.  Sending units differ as well as the wiring on the plug. 
1985 C30 Custom Deluxe Ext. cab 5.7L TH400 4.56 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline lumartin1989

  • Newbie
  • Posts: 10
  • Newbie
Re: Idiot Lights vs. Gauges in Dash
« Reply #2 on: April 30, 2018, 02:02:58 PM »
I assumed as much, this is probably a stupid question but where is the sending unit for the temperature gauge? Is it near the thermostat, or in the engine block somewhere. I really only care about the coolant temp gauge, so I was thinking of just taking that out of the  cluster I got and putting it into the one on the truck right now.

I might run to the junkyard to get a sending unit and maybe a different wire harness, I suppose? 

Online zieg85

  • Carl
  • Site Supporters
  • Senior Member
  • ******
  • Posts: 6771
    • 73-87 GM squarebody extended cab and conversions up to 91 R/V series
Re: Idiot Lights vs. Gauges in Dash
« Reply #3 on: April 30, 2018, 05:05:15 PM »
Temp sending unit should be on the passenger head.  You would be better off getting a quality independent gauge, perhaps a Stewart Warner.  I actually plan to install a triple pod and have them in addition to the warning lights.  I have always preferred having both. 
1985 C30 Custom Deluxe Ext. cab 5.7L TH400 4.56 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline lumartin1989

  • Newbie
  • Posts: 10
  • Newbie
Re: Idiot Lights vs. Gauges in Dash
« Reply #4 on: April 30, 2018, 05:09:19 PM »
I actually like that idea a lot.

Do you have a link for that gauge, is that a pretty simple thing to set up, I'm a bit of a novice when it comes to electrical stuff?

Offline 75gmck25

  • Registered Users
  • *
  • Posts: 205
  • 1975 GMC K25 Camper Special, 350/TH350/NP203
Re: Idiot Lights vs. Gauges in Dash
« Reply #5 on: May 01, 2018, 07:08:55 AM »
The sending units are different on a gauge cluster, but the wiring plug is usually the same.  However, where the wires run in the harness may be different.  However, you do need to make sure the new cluster matches your truck year, since some wiring changed from year to year.  For example, on my '75 truck I can use a 73-75 cluster, but in about '76 they switched from mechanical to electric oil pressure gauge, and from an ammeter to a voltmeter, so other clusters will not directly work with my truck.

The stock temp sending unit is in the driver's side head, in the middle of the side below the spark plugs.  You can look down between the plug wires and see it sticking out of the block.  Its fairly easy to get a stock gauge cluster working by adding the right sending units, but then you will usually have a temp gauge without any numbers.   It really doesn't make me feel very good to have a gauge with no numbers.   You also have to make sure you get the sending unit that matches the gauge year, since the specs changed over the years.

There is another identical threaded hole in the passenger side head, just in case you want to add a temp gauge without getting rid of the light you already have.   I used that port to install a digital sending unit and gauge from Summit (cheapest choice), and it works really well.  I find it very reassuring to know that my truck is running at exactly 192 degrees (or some other temperature), instead of just looking for mid scale on the stock gauge.

Many of the cheapest aftermarket gauge sets use a mechanical oil pressure and mechanical temp gauge, which are harder to install because of the lines to the sending unit.   And a mechanical oil pressure gauge actually has oil in the line to the gauge, so you can get an oil leak into the cab.  I strongly suggest you avoid that choice.  Look for electric gauges, and buy a set of voltmeter, temp and oil pressure that are the same design.

Bruce

Offline lumartin1989

  • Newbie
  • Posts: 10
  • Newbie
Re: Idiot Lights vs. Gauges in Dash
« Reply #6 on: May 01, 2018, 02:35:04 PM »
Thanks for the reply I found that pretty easily, looks like it has a greenish wire coming out of it. So from what you are saying that end of the wire will go into a stock sending unit that will read for the gauge? When you say wiring harness, are you talking about where it goes into by the firewall, kind of close to the steering shaft?

My hope was to try and find one from a mid-80s truck, mine is an 86 K10.

Sorry I didn't understand this below?

"Its fairly easy to get a stock gauge cluster working by adding the right sending units, but then you will usually have a temp gauge without any numbers.   It really doesn't make me feel very good to have a gauge with no numbers.   You also have to make sure you get the sending unit that matches the gauge year, since the specs changed over the years."

When you say a gauge without numbers, maybe you are referring to some of the older gauges? I got a cluster from an 85 Chevy K10 (mine is an 86 K10) and it does have the numbers on it (it shows 100, 210, and 260).

Offline 75gmck25

  • Registered Users
  • *
  • Posts: 205
  • 1975 GMC K25 Camper Special, 350/TH350/NP203
Re: Idiot Lights vs. Gauges in Dash
« Reply #7 on: May 01, 2018, 05:16:01 PM »
The older temp gauges have no numbers, but it sounds like your newer truck does have numbers on the face.   Mine just has Cold, Hot and lines at the 1/4, 1/2 and 3/4 marks.

I have considered swapping a newer temp gauge into my '75, since the correct temp sender for my '75 is very hard to find.   There is a discontinued Delco part number, but most cross-reference tables list a newer sending unit that does not provide the correct gauge readings.  Classic Industries sells one that is supposed to be correct, but it costs $27 (vs. a stock $9-10 sending unit).

Bruce

Offline RyanG

  • Newbie
  • Posts: 8
  • Newbie
Re: Idiot Lights vs. Gauges in Dash
« Reply #8 on: May 16, 2018, 12:10:24 AM »
They sell a gauge pillar in the store on this site (http://store.73-87chevytrucks.com/). I haven't used it yet but I plan on ordering one. I have however done a lot of work to my gauge cluster. I have installed several autometer gauges in the factory locations, it was a lot of work. I would recommend getting the gauge pillar and just putting aftermarket gauges in that location. Of course this option is a little expensive and doesn't really give you that original factory look.....

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 16881
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)