Big Blue's Transformation

[ArdWrknTrk]

Yes, 42 is the answer. But, it just seems like there are that many relays on the firewall. However, as it turns out, there's one more than I thought - I forgot the "tank selector relay".

Given that, I'm short at least one relay in the PDB. So I may have to use the Trailer Relay cover that puts some relays on the side of the PDB if I want to get them off the firewall.

'86 doesn't use a selector relay, just the switch in the climate control bezel..

[Gary Lewis]

Maybe you need one of these relay panels:

What's that off of, Bill? There' no place for fuses? Just LOTS of relays?

Jim - I was counting today and came up with three factory relays under there, but when I got into the house couldn't come up with the third one after fuel pump and trailer. Until I saw this in the '85 EVTM. Yep, that's the third relay.

But, as you said, the '86 trucks didn't have the fuel tank relay. Here's the '86 EVTM page. So, I could bypass the relay such that the tank selector switch actually powers the pumps. But, the switch changed for '86, so is it rated for the pump and the '85 switch isn't? http://www.garysgaragemahal.com/uploads/6/5/8/7/65879365/thinking-26_orig.jpg

[ArdWrknTrk]

What's that off of, Bill? There' no place for fuses? Just LOTS of relays?

Jim - I was counting today and came up with three factory relays under there, but when I got into the house couldn't come up with the third one after fuel pump and trailer. Until I saw this in the '85 EVTM. Yep, that's the third relay.

But, as you said, the '86 trucks didn't have the fuel tank relay. Here's the '86 EVTM page. So, I could bypass the relay such that the tank selector switch actually powers the pumps. But, the switch changed for '86, so is it rated for the pump and the '85 switch isn't?

I imagine so.

I don't have them both to compare, but I was just thinking that my '87 didn't have a relay, and you seemed to be looking for an answer that didn't involve a relay.

So, I thought I'd mention it.

[ArdWrknTrk]

What's that off of, Bill? There' no place for fuses? Just LOTS of relays?

Jim - I was counting today and came up with three factory relays under there, but when I got into the house couldn't come up with the third one after fuel pump and trailer. Until I saw this in the '85 EVTM. Yep, that's the third relay.

But, as you said, the '86 trucks didn't have the fuel tank relay. Here's the '86 EVTM page. So, I could bypass the relay such that the tank selector switch actually powers the pumps. But, the switch changed for '86, so is it rated for the pump and the '85 switch isn't?

You don't see the penta-star?

Hmm, what could it be from?????

[Nothing Special]

I see you also grok things and have read Hitchhikers Guide to The Galaxy.

I've always thought that Jim was a hoopy frood who always knows where his towel is.

 

[85lebaront2]

You don't see the penta-star?

Hmm, what could it be from?????

1990 Lebaron convertible, now installed in my 1986 Lebaron convertible.

[Gary Lewis]

1990 Lebaron convertible, now installed in my 1986 Lebaron convertible.

Both switches are DPDT. But the '85 switch is a 4-pin and the '86 switch is a 6-pin. And the extra 2 pins are used to bring out two contacts that were unused in the '85 switch. The effect is that the '86 switch uses both poles in parallel to power the pump where the '85 switch just uses one pole. So, I'd say the current rating is 1/2 in the '85 switch and it needs the relay.

I'll have to look and see what I have, but I don't know that I have an '86 switch. And if I do it'll require some rewiring. Not sure whether that will be easier than just going with the trailer relay mount.

[ArdWrknTrk]

Both switches are DPDT. But the '85 switch is a 4-pin and the '86 switch is a 6-pin. And the extra 2 pins are used to bring out two contacts that were unused in the '85 switch. The effect is that the '86 switch uses both poles in parallel to power the pump where the '85 switch just uses one pole. So, I'd say the current rating is 1/2 in the '85 switch and it needs the relay.

I'll have to look and see what I have, but I don't know that I have an '86 switch. And if I do it'll require some rewiring. Not sure whether that will be easier than just going with the trailer relay mount.

The two other pins drive the motor in the selector valve back and forth.

They're not carrying "extra" current to the pumps.

I was just pointing out that you can (fairly) easily work around needing a selector relay.

What you do is up to you.

[Gary Lewis]

The two other pins drive the motor in the selector valve back and forth.

They're not carrying "extra" current to the pumps.

I was just pointing out that you can (fairly) easily work around needing a selector relay.

What you do is up to you.

Here's the '86 switch from the EVTM, and the extra two pins are tied to the other pins in the harness, paralleling them, surely for current capacity.

But, in the light of day I'm questioning moving the selector relay and the trailer relay. Why not leave them where they are in the factory relay holder? They are tucked back out of the way and are working fine.

The relay to move is the fuel pump relay as instead of being pulled in by the oil pressure switch the ECU wants to pull it in. And, it wants to monitor that it has pulled in. So it is already wired up in the PDB and I might as well use it.

[85lebaront2]

Here's the '86 switch from the EVTM, and the extra two pins are tied to the other pins in the harness, paralleling them, surely for current capacity.

But, in the light of day I'm questioning moving the selector relay and the trailer relay. Why not leave them where they are in the factory relay holder? They are tucked back out of the way and are working fine.

The relay to move is the fuel pump relay as instead of being pulled in by the oil pressure switch the ECU wants to pull it in. And, it wants to monitor that it has pulled in. So it is already wired up in the PDB and I might as well use it.

Glad you took a second look and remembered the carbureted setup was for break-in and not permanent. For now, if you want to retain an oil pressure operated pump system, simply change the wiring on the existing oil pressure switch to ground the relay coil or change the switch to a late model "sender" which is a reverse function switch (open with no pressure, closed with pressure).