There's been a thread on the International Merkur Owners' Network about why the liftgate latch is disabled while the engine is running. Many of us have chafed at having to turn off the engine to open the liftgate. Well, my liftgate latch works just fine, whether the engine is running or not, thanks to the modification I describe here.

The circuit built into our Scorpios is very simple. As shown here, it consists of two parallel paths through the Liftgate Release Relay, which is located in the main Fuse & Relay Panel under the hood by the LH windshield wiper.

When the engine's not running and the doors aren't locked, then closing the Liftgate Lock Switch closes the Liftgate Release Relay and activates the Liftgate Release Solenoid. What we want to discover is a way to remove the restriction that the engine can't be running. Sounds simple? It is.

The trick is to find a way to modify the circuit reversibly so that if you make a mistake you haven't forced yourself into an expensive repair to get back to where you were before you started.

I devised such a scheme. It works perfectly. There are no changes in the harness, the liftgate, the switches, or any other device or wiring. All other functionality in the car remains unaffected. I did the work entirely in the comfort of my workshop while the car sat unmolested. Now the liftgate latch no longer cares whether the engine is running, but it still mimics the locked/unlocked condition of the doors. No component is under more physical or electrical stress than it was previously. And I can undo the change in less than two minutes.

What's the secret? I modified the Liftgate Release Relay. Ta-DAHHH.

I simply energized both paths through the Liftgate Release Relay from the always-hot lead. The concept is straightforward, but the implementation demanded some ingenuity and a lot of care. I insisted that all the modifications be internal to the relay, as shown below. That would have allowed me to pop another relay into the socket if I'd messed up. (It happens to the best of us.)

I'll describe the changes; but if you choose to attempt this modification yourself, please heed this warning:

It's possible to do this work wrong. This procedure worked for me because I took my time and didn't undertake any step until I was sure I understood it. All the risk for any consequential damage lies with the doer.

If you do inflict permanent damage on your relay, you can order part # E7RY 14N089A @ $27.83 from your dealer. Or you can do what I did: find a scrapped Scorpio and walk away with every relay in the whole car for $20. (The code "E7RY" indicates that in the Ford family this part is exclusive to the Scorpio; no other Ford vehicle shares it - hence the outrageous price.)

OK, here's the process.

1. I located the Liftgate Release Relay. It's tan. So are several others. They're all identical. Realizing I might botch the job, I left the Liftgate Release Relay in place and selected one I wouldn't miss for a while if things went badly. I chose the Heated Seats Relay and removed it from the panel. Owners of the '88 model have a more restricted choice.

2. Using two slender jeweler's screwdrivers, I spread the tan plastic cap and slid it off the relay's base to reveal the interior. The coil of fine wire inside is wholly unprotected. In this and subsequent steps the coil was vulnerable to catastrophic abrasion from a minor slip of a tool.

3. The relay's coil runs between the slender upright posts that extend from terminals 85 & 86, identified on the underside of the relay's black base. The switched contacts are on terminals 87 and 30. The goal of steps 4 - 8 was to fashion a physically and electrically sound shunt that would connect the interior post of terminal 86 to terminal 87 as shown in this diagram. Severing the connection between terminal 86 and its interior post came at the end of the process. In that way I left the only irreversible step until the last minute.

4. Recessed into the inside of the black plastic base there's a small circuit element the Scorpio's wiring diagram identifies as a fuse (I have my doubts; but let's humor Ford, eh?) That fuse has silvery leads running to terminals 85 and 86. With a small screwdriver I carefully raised the fuse's lead that's routed to terminal 86. I raised it high enough that there'd be room to slip a bare wire under it in step 7.

5. There's no subtle way to connect a shunt to terminal 87 inside the relay, so I drilled a tiny hole through the black plastic base to allow me to solder the wire to the terminal's fat blade just outside the base. By "tiny" I mean a hole just large enough to accommodate a single strand of wire such as one of the strands that make up a twisted bundle in lamp cord. We're not talking about a lot of current here; after all, consider how fine the coil's wire is.

But I had to put the hole in the right place and I had to drill it very gingerly, because the drill's tip was pointing directly at that vulnerable coil. The right place turned out to be along the broad surface of terminal 87 that faces terminal 30, with the hole emerging close to the terminal-86 lead of the fuse. I used a suction-based hobby vise to hold the relay while I drilled with a Dremel tool.

6. I gently slipped a bare wire though the hole from the outside, using a toothpick to progressively curl it away from the coil and toward the fuse's raised lead. Eventually I had enough slack inside to permit wrapping the curl completely and tightly around the fuse's lead. I temporarily left the surplus wire extending outside along the face of terminal 87.

7. With a rechargeable 15 watt iron I carefully and sparingly soldered the curled wire to the fuse's lead. This was a delicate step, because I didn't know how much heat the fuse could absorb without damage. My usual ploy is to let the iron reach its operating temperature, then flow the solder as quickly as possible and get the heck out of there.

8. With a 30 watt AC iron I soldered the free end of the wire to the blade of terminal 87 as close as possible to the black plastic base and with the smallest achievable bead. (A 15w iron can't heat the terminal sufficiently.) This completed the electrical work, so I confirmed the circuit by checking it with an ohmmeter between exterior terminals 86 and 87. Then I snipped away the surplus wire.

9. I gently urged the fuse's raised lead back into its channel in the base, then I put the tan plastic cover back on the relay. I was about to sever the exterior blade of terminal 86, and I didn't want any conductive debris inside the relay.

10. With a thin abrasive wheel in the Dremel tool, I sliced off terminal 86's blade and ground it flat to within a 32nd of an inch of the outside of the black plastic base. I left a little of it exposed to ensure the mechanical integrity of the interior post. Jim Hansen has suggested that putting a piece of insulating tape over the remain stub of 86 will add protection against unwanted contact. Good idea, Jim; thanks.

11. I cleaned the relay's exterior so no chips or metallic dust would get pushed into the Fuse & Relay Panel. I also put a daub of white paint on the top of the tan cover so I'd never have any doubt about which circuit it was in.

12. I pulled the Liftgate Release Relay and put it in the Heated Seats Relay's socket, then I put the modified relay into the Liftgate Release Relay's socket.

13. I tested the new relay in every imaginable variation of conditions, including a check of the Fuel Filter Door circuitry to make sure I hadn't affected other engine-not-running devices. Then I took a 10-mile drive as a final confirmation that the car had been otherwise unaffected.

I hope that this narrative will be useful to you as an illustration of how to design and execute modifications. This wasn't a particularly challenging one intellectually, but it did require a careful hand and some patience. The reward is great. I might just stop every few feet and open my liftgate for the sheer joy of it....

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