5303 wiring diagram

[j.m.jackson]

So I went to install the electronic tach, water temp, and oil pressure gauge, figuring that I could use the spare wires in the harness to get the signals to the drivers station. The panels are numbered, so why not.

What I didn't know is every panel starts at number 1.

So my next option is to tone out the lines and see what is what between the engine panel and drivers panel. Unfortunately my toner is at work, so i won't have it until Monday evening.

Anyone have an electrical diagram, or am I going to have to bite the bullet and buy it for $75 from coachinfo.com?

[Paso One]

GM book number X6326 has about 25 + pages of wiring diagrams covering the 5303 Suburban and Transit.
I looked up a Suburban and stud 38-40-28-26- and 20 are all spares going from engine compartment to drivers panel.  that will at least give you somewhere to start.

[TomC]

Or you could do what I did-buying 5-3 wire 50ft extension cords of all different colors. Nylon tie them together and run them from the engine compartment to the driver's compartment. Now I have 15 wires available to do what I want with. So far, I've used 2 for the tachometer driver, and another 2 for the generator for cruise control. Still plenty left for additional gauges. Good Luck, TomC

[Paso One]

I took your suggestion Tom and wish I did it sooner

[j.m.jackson]

I haven't laid my eyes on the voltage regulator for the 50dn alternator. When I pulled off the panel up front at the drivers station, lo and behold there sat a standard looking black metal covered regulator.. Is that the one for the 50dn? If so, can I pull a tach signal from there, or is the signal not up there for it?

[j.m.jackson]

My tach wants a signal from the W or R terminal... Is the R terminal on the 50DN the one towards the back?

Also found the pulses per revolution count that I needed on here.

Note 1 ->For Detroit Diesel Delco gear driven 50DN
           270 Amp 24 volt alternators "R" Terminal hookup
           The "R" terminal output is 12 volt -
           Most 6V92TA's are: (2.93 gears & 6 pulses per Revolution=17.58 pulses/rev)
           Older 6V92's can be(2.75 gears & 6 pulses per revolution=16.5  pulses/rev)
           Older 8V71's can be(2.29 gears & 6 pulses per revolution=13.74 pulses/rev)  

I hope the 12V version is also 6 pulses per revolution.    

[j.m.jackson]

Ok, so the device up by the dash that looked like a voltage regulator is the warning buzzer.

I used the following:

26 engine -> 9 driver (oil pressure)
28 engine -> 86 drive (water temp)
38 engine -> 89 driver (tach)

Used my toner tool to trace them from the engine panel to the front.

[j.m.jackson]

Dashboard reconfigured. I had voltage and air pressure before, that was it.

[richard5933]

Nicely done.

How accurate is the tach? I've got to replace mine, but wasn't sure how good the alternator driven units worked.

Richard

[j.m.jackson]

Seems accurate, I checked it with an optical reflective tach on the camshaft. It's running off the R terminal of the 50dn alternator, running through the original coach harness, and isn't bouncy. I set the dip switches for 12-17 pulses per revolution and adjusted it for the idle and high idle rpms that i measured at the cam.

RPMs that I measured at the cam were:

474 rpm idle
705 rpm high idle
1985 rpm wide open, no load.

[j.m.jackson]

On the dash, I used some 1/4 inch thick HDPE plastic with a textured finish to mount the 2-1/16th gauges. The dash had 3 2-5/8th holes, which were not useful to me.

The left hand hole was 3-3/8. That fit the tach. I drilled a 3-1/8 hole for the air pressure gauge in the right side.

I then used rustoleum black hammered paint to finish it off, and my daughter used some testors black paint on the surrounds of the warning lamp clusters.

I need to get some black automotive door edge guard to go around the perimeter of the dashboard to cover the edge and prevent rattles.

[j.m.jackson]

Sigh. So I got some LED 57 bulbs to replace the indicator lamps. I had to mash the base somewhat to oblong them to fit snugly in the socket. The lights in the sockets with 2 wires wouldn't work (all warning lights (trans oil,eng hot, eng oil)). On a hunch, I tested them with a voltmeter. The dang center pin is negative, and the outside is positive. Now I get to rewire 4 sockets.