Author Topic: 1985 GMC K10 build  (Read 23171 times)

Offline bd

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Re: 1985 GMC K10 build
« Reply #195 on: August 11, 2017, 05:59:04 PM »
For 1979 - 1990 vintage temperature gauges, the lowest (cold) line of the gauge corresponds to 1,365 ohms of sender resistance, the center line of the gauge corresponds to 96 ohms, and the highest (hot) line corresponds to 55 ohms.  In other words, disconnecting the gauge from its sender will deflect the gauge needle fully CCW, below "cold," whereas grounding the sender wire will cause full scale CW deflection, past the maximum "hot" line.
Rich
It's difficult to know just how much you don't know, until you know it....
In other words... if people learn by making mistakes, by now I should know just about everything!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline 1967KaiserM715

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Re: 1985 GMC K10 build
« Reply #196 on: August 11, 2017, 08:23:23 PM »
For 1979 - 1990 vintage temperature gauges, the lowest (cold) line of the gauge corresponds to 1,365 ohms of sender resistance, the center line of the gauge corresponds to 96 ohms, and the highest (hot) line corresponds to 55 ohms.  In other words, disconnecting the gauge from its sender will deflect the gauge needle fully CCW, below "cold," whereas grounding the sender wire will cause full scale CW deflection, past the maximum "hot" line.
Would disconnecting bring it to about 9 o-clock, or just under the "cold" line? Grounding did peg needle to about 3 o-clock, but disconnecting only brought it under the "cold" line.

In other news, fixed my wiring for brake lights and park lights. They now work as they should, had the wiring crossed.

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1996 Jeep Cherokee(Daily) 1975 Beetle(not running)
1985 Mercedes 300D(not running) 1985 GMC K10(not running)
1952 M35              1967 M715(not running)

Offline bd

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Re: 1985 GMC K10 build
« Reply #197 on: August 11, 2017, 08:29:59 PM »
Sounds about right.  If you want to test the gauge, substitute a 56-ohm 1/2-watt resistor for the sender; the gauge should read mid-scale.  But it sounds like it has a faulty or incorrect sender.
Rich
It's difficult to know just how much you don't know, until you know it....
In other words... if people learn by making mistakes, by now I should know just about everything!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline 1967KaiserM715

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Re: 1985 GMC K10 build
« Reply #198 on: August 12, 2017, 06:51:32 AM »
I'll see if I have a resister and test. In the meantime do you have a part number for the sender? My gauge reads from 100 to 260. Searching is yielding me several numbers with no clear idea about which gauge it goes to.

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1996 Jeep Cherokee(Daily) 1975 Beetle(not running)
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1952 M35              1967 M715(not running)

Offline 1967KaiserM715

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Re: 1985 GMC K10 build
« Reply #199 on: August 12, 2017, 07:28:12 AM »
A 47, and 10 ohm, 1/4 watt resisters in series, only brought the gauge to the second tick mark, 1/4 gauge reading.

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Current Vehicles:
1996 Jeep Cherokee(Daily) 1975 Beetle(not running)
1985 Mercedes 300D(not running) 1985 GMC K10(not running)
1952 M35              1967 M715(not running)

Offline bd

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Re: 1985 GMC K10 build
« Reply #200 on: August 12, 2017, 10:27:53 AM »
...do you have a part number for the sender?

For an '85 K10 with 6.2C/J and gauges:  OEM P/N-25037346 (ACDelco #213-80).


A 47, and 10 ohm, 1/4 watt resisters in series, only brought the gauge to the second tick mark, 1/4 gauge reading.

That was a typo.  I meant to type 96 ohms; 56 ohms should deflect the needle to "hot."  Check and clean the connections between the slewing resistor on the back of the gauge and the gauge terminals.  Otherwise replace the gauge.
Rich
It's difficult to know just how much you don't know, until you know it....
In other words... if people learn by making mistakes, by now I should know just about everything!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline 1967KaiserM715

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Re: 1985 GMC K10 build
« Reply #201 on: August 12, 2017, 02:55:23 PM »
Replaced gauge, seems to work now, will go for a drive and verify.

While I had cluster out (again) I decided to pull fuel gauge to see if I could get it to function off the truck (pulling wires, and grounding/de-grounding did nothing) I noticed a missing spring clip, and found a portion of it along the bottom of the cluster-i found the rest of it under my floor mat. Fuel gauge appears to work now, at least it goes up to about where it should.



I had removed and burnished all spring clips and the circuit board before installing on truck- also made sure spring clips were tight. Apparently that clip was on the verge of failing and I failed to notice. I rechecked a few others, they all appear to be fine.

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1996 Jeep Cherokee(Daily) 1975 Beetle(not running)
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1952 M35              1967 M715(not running)

Offline 1967KaiserM715

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Re: 1985 GMC K10 build
« Reply #202 on: August 12, 2017, 04:28:53 PM »
Temp gauge still not working right, I put in a gauge I know came from a Diesel truck, reads 240 as high. This makes me feel like there is an issue with the wiring someplace. BUT I will test with a resister to see what the gauge reads. I really should just order the right parts and make my own tester, so I can test spare gauges and throw out any that don't "work"

the New temp sender was a standard TS76, which does correspond to the OEM part number supplied.

And Thanks bd for being so helpful. Also to VileZambonie and the many others who have lent their wisdom.
Current Vehicles:
1996 Jeep Cherokee(Daily) 1975 Beetle(not running)
1985 Mercedes 300D(not running) 1985 GMC K10(not running)
1952 M35              1967 M715(not running)

Offline VileZambonie

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Re: 1985 GMC K10 build
« Reply #203 on: August 12, 2017, 06:11:43 PM »
Try WT359P sending unit
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Offline 1967KaiserM715

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Re: 1985 GMC K10 build
« Reply #204 on: August 12, 2017, 06:34:20 PM »
A 47, and 10 ohm, 1/4 watt resisters in series, only brought the gauge to the second tick mark, 1/4 gauge reading.

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I screwed up here, been so long in reading resister values, I had to look them up to make sure I was grabbing the right ones, still read wrong, it was a 47 and a 100ohm resister that brought Original(100 to 260) to a 1/4 gauge reading. This was attaching the resisters in series to the spade plug in engine bay and grounding out.

On the newer gauge, two 47 ohm resisters brought the gauge to a 3/4 reading, but the 100 and 47 ohm resisters brought the gauge reading to 1/2 way. Trying to find the parts to make a gauge tester, via bd's informative post on functional test on gauges.
Current Vehicles:
1996 Jeep Cherokee(Daily) 1975 Beetle(not running)
1985 Mercedes 300D(not running) 1985 GMC K10(not running)
1952 M35              1967 M715(not running)

Offline 1967KaiserM715

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Re: 1985 GMC K10 build
« Reply #205 on: August 13, 2017, 11:55:25 AM »
Not sure, seemed like a good idea in the vast space of my mind, I think I'll try something a little different on the other side. I plan on running a steel trap door over it.



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Current Vehicles:
1996 Jeep Cherokee(Daily) 1975 Beetle(not running)
1985 Mercedes 300D(not running) 1985 GMC K10(not running)
1952 M35              1967 M715(not running)

Offline VileZambonie

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Re: 1985 GMC K10 build
« Reply #206 on: August 13, 2017, 12:11:17 PM »
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              ⌠ŻŻŻŻŻ'   [☼===☼]
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Offline bd

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Re: 1985 GMC K10 build
« Reply #207 on: August 13, 2017, 01:13:23 PM »
That's great idea, albeit mimic the design in 12-ga marine stainless and mortise the surrounding wood with a router for a flush fit.
Rich
It's difficult to know just how much you don't know, until you know it....
In other words... if people learn by making mistakes, by now I should know just about everything!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline 1967KaiserM715

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Re: 1985 GMC K10 build
« Reply #208 on: August 13, 2017, 02:02:28 PM »
How about mounting it parallel with the floor and use a flush mount cover

https://www.summitracing.com/parts/mor-85700?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-moroso&gclid=EAIaIQobChMI6uTViNnU1QIVgSOBCh2POwt_EAQYASABEgI-HvD_BwE
Whatever I do is going to require a new/different neck and/or hose. So not a bad idea, just need to think out drivers side a little better. Plus, because I am putting side boards on, I want to be able to fill without having to remove sideboards or anything I might be carrying.

My attempt was one of those times where you want to think before cutting...sort of like the measure twice cut once.

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Current Vehicles:
1996 Jeep Cherokee(Daily) 1975 Beetle(not running)
1985 Mercedes 300D(not running) 1985 GMC K10(not running)
1952 M35              1967 M715(not running)

Offline 1967KaiserM715

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Re: 1985 GMC K10 build
« Reply #209 on: August 13, 2017, 04:55:16 PM »
Try WT359P sending unit
Picked one up today, installed it, seems to have done the trick, it doesn't peg out, although it does read high, at 170/180° on my IR thermometer, it reads 200-210° on the gauge. Now when I did the resister test(probably slightly inaccurate my method) did show my gauge would read high (94 ohms showed 3/4 (210°), the previous gauge read at 1/4 (140ish?) with a 147ohm resister, so I would have to think the original gauge is/was a better match for this sender.

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Edit: further testing on gauges will be done before swapping, still working on locating the pieces to make a tester, I want to be able to bench test, so a self powered 12v unit would be key here.
« Last Edit: August 13, 2017, 04:58:03 PM by 1967KaiserM715 »
Current Vehicles:
1996 Jeep Cherokee(Daily) 1975 Beetle(not running)
1985 Mercedes 300D(not running) 1985 GMC K10(not running)
1952 M35              1967 M715(not running)