Finally left me stranded

[ak diesel driver]

no it's not wrong just a different way. Leroy's allows you to NOT CUT any factory wires. as far as tapping into the output of the glow controller vs the input to it shouldn't make any difference as all it's doing is triggering a relay

 

[SnowDrift]

At any rate, I think we're heading down a rabbit hole with the wiring schematic and such. side issue, to my question about the harness.

As some may recall, this whole system operates flawlessly after the engine has warmed the components underneath the hood or if I jiggle the relay harness enough. Thus, I suspect an intermittent connection failure for some reason due to the colder temperature - much the reason I suspect my soldered connection on my OPS connector I made up or the OPS connector, itself. Now that I know Leroy's not getting power from the OPS or touching the connector in any way, I can abandon the notion of getting harness photos.

 

[SnowDrift]

no it's not wrong just a different way. Leroy's allows you to NOT CUT any factory wires. as far as tapping into the output of the glow controller vs the input to it shouldn't make any difference as all it's doing is triggering a relay

I used this schematic, except I did not cut a single factory wire, nor did I tap into a factory wire. This is what I'm talking about when I said I made up my own OPS connector (I modified an old OPS to accept the factory plug).

Ok, Leroy, so based on what AK said about the power wire from the glow plug relay agreeing with this schematic, are you now open to looking at the "prime" addition being added to your harness? If so, then when would one be available for sale?

 

[1994ch]

No, it takes a 10-15 minute drive until it starts working. I have oil pressure as soon as the engine fires.

IIRC the OPS has two circuits in it. It will indicate oil pressure on the gauge even if the LP side of the circuit has failed.

 

[1994ch]

I do know that when my OPS failed (was not running the lift pump) it still indicated just fine on the dash.

 

[Will L.]

IIRC the OPS has two circuits in it. It will indicate oil pressure on the gauge even if the LP side of the circuit has failed.

Correct.

Sorry Snowdrift, I didn't realize you already suspected open circuit- I thought you were trying to determine bad component and trying to upgrade system to fill filter at service while bypassing a component at same time.

We learned LP relay is better in the fleets also. GM knew the ops took the load, it's engineered to wipe them out for maintenance back to dealerships. Notice it's JUST hard enough to change most people don't want to do it themselves? I learned lots working with automotive engineers from different mfrs. Even more when a good friend became one.

In the big fleet, I did mine different- I always needed a couple accessories, so off the driverside battery positive, ran a fuseable link to a 4 pack of relays. On one I would carry the 10 gauge and a positive signal wire down the frame along to the LP. Using a new male and female connector (same as LP) Supply plug from harness fed signal to relay, and new 10 gauge fed LP.

Back up at the relay a secondary tap on ground activation got a 3-4" jumper wire with alligator clip. We clipped alligator to plastic relay housing. When doing filter just hook alligator to mounting bolt . A switch is cleaner, but I was given a box of 100 alligators for free from a supplier so....

100 ways to skin a cat. Best to let the dog eat the whole thing.

 

[Burning oil]

Im surprised you are not frying your relay, popping a fuse or making the magic smoke. Tapping the GP relay stud puts a huge load on LP relay. I'll study the schematic you posted to see if I glean anything from it.

I have always said Im open to do the prime feature but that is may cost more to do.

I had done what you did with modifying an old OPS at one time this way there is no need to cut any factory wires, but thats not a good solution IMO if you feeding the power though the factory OPS connector leading to LP.

You might even pick up a # or 2 with my harness.

IIRC the OPS has two circuits in it. It will indicate oil pressure on the gauge even if the LP side of the circuit has failed.

I do know that when my OPS failed (was not running the lift pump) it still indicated just fine on the dash.

You correct sir.

 

[Husker6.5]

It's called Field Engineering, Will. Also known as Military Expediency.

 

[SnowDrift]

40 amp relays - glow plug circuit is 30, right?

 

[Will L.]

It's called Field Engineering, Will. Also known as Military Expediency.

We always called it- not walking home in the 115 f* desert heat. The f* didn't always stand for fahrenheit.

I agree with Leroy, I wouldn't want to add load to the glow plug controller. If only pulling signal to relay -ok, but not power to the LP. Already a heavily taxed circuit.

 

[SnowDrift]

I agree with Leroy, I wouldn't want to add load to the glow plug controller. If only pulling signal to relay -ok, but not power to the LP. Already a heavily taxed circuit.

Not even to just power the relay for the LP?

 

[Husker6.5]

Pull power through the relay to the LP from the AUX terminal stud on the underhood fuse block located on the passenger firewall on a '95, on the driver fender liner on '96+. It comes straight from the battery positive cable on '95-down and off the Alt on '96+.

 

[Will L.]

To control the relay yes. That's considered the signal wire. All it does is turn on the relay.

But not the power supply that goes threw the relay to the pump.
I don't know where Leroy is pulling his from, I came straight from the battery.

 

[Husker6.5]

The SIGNAL to the relay's coil should be the run power coming from the OPS to the LP (from the unplugged OPS to LP connector) with the other coil lead grounded. LP power to the relay should come from a direct battery source (fuse it) to the relay. Power out from the relay contacts should now go to the LP's power terminal via a new LP connector.

 

[Burning oil]

Dug up this old post. Works but not the way to do it IMO. click >>>#42

 

[SnowDrift]

Pull power through the relay to the LP from the AUX terminal stud on the underhood fuse block located on the passenger firewall on a '95, on the driver fender liner on '96+. It comes straight from the battery positive cable on '95-down and off the Alt on '96+.

Do you mean Aux A and B, here? These are always powered, not key on power. I do have power coming through one of these terminals after the engine is running.

To control the relay yes. That's considered the signal wire. All it does is turn on the relay.

But not the power supply that goes threw the relay to the pump.
.

Yes, glow plug relay post sends power to relay for LP during WTS.

 

[SnowDrift]

Dug up this old post. Works but not the way to do it IMO. click >>>#42

Yes, that's pretty much what I did, too. You've gone a different route with your harness, though. I think you're pulling power from the wire at the LP, back up to the relay and then back to the LP. This way, it's not necessary to make up this connector with the used OPS, which is a real hassle.

Pull power through the relay to the LP from the AUX terminal stud on the underhood fuse block located on the passenger firewall on a '95, on the driver fender liner on '96+. It comes straight from the battery positive cable on '95-down and off the Alt on '96+.

Do you mean Aux A and B, here? These are always powered, not key on power. I do have power coming through one of these terminals after the engine is running.View attachment 47530 View attachment 47531

 

[Burning oil]

Do you mean Aux A and B, here? These are always powered, not key on power. I do have power coming through one of these terminals after the engine is running.View attachment 47530 View attachment 47531



Yes, glow plug relay post sends power to relay for LP during WTS.

Yes thats were I grab power also. Stud A or B on the back of fuse box. Has the bat cable running right to it.

 

[Husker6.5]

Yup, those are them. I used them for the power (each fused) to the 4 relays for my 55W HID fog, driving, Lo and Hi beams. I used the old Lo and Hi beam connectors on the driver side to energize the relay coils, and built my own diode pack to use the passenger side Lo and Hi beam connectors to make my own All On on Hi Beam conversion kit.

Those terminal posts are really handy for pulling power for lights, accessories, stereo amps, etc.

 

[SnowDrift]

Leroy, you can let me know if you're interested in building up a different harness with the prime function in it. I'm in the market and I'm sure there will be others.