De-fuse a Saturn for towingby George Mullen
After ten years of towing a Ford Mustang with the rear wheels on a tow dolly, I decided it was time to move up to something easier, namely towing with all four wheels on the ground. My wife and I decided to buy a 2001 Saturn SW2 wagon, one of the last ones Saturn made. At the time of the sale I was aware that my Saturn was wired in such a way that it became necessary for the manufacturer to recommend removal of one fuse (labeled IGN1/4) before towing the vehicle. While the vehicle can be safely towed with the fuse in place the owner runs the risk of draining the battery if left in the towing configuration for longer than a day’s trip. This occurs because the Body Control Module is powered through that fuse with the key in the ACC position. See Saturn’s Technical Information Bulletin number 00-T-33 issued June, 2000.
With an extensive background in the repair of electrical/electronic equipment in military combat aircraft it has been and still is my firm conviction that repetitive fuse-pulling is not a substitute for a switch. Fuse holders are seldom designed to take the amount of wear and tear caused by repetitive removal and insertion of the fuse. As noted in the aforementioned information bulletin fuse terminal damage can occur if the fuse is not removed properly (pulling straight up, rather than rocking side-to-side). It was not difficult to come to the conclusion that flipping a single switch was quicker and much easier than opening the hood, removing the fuse box cover, removing the appropriate fuse and stowing it someplace where it would not get lost, replacing the fuse box cover and closing the hood. I was also concerned that breaking the integrity of the manufacturer’s wiring to install a disconnect switch might void the Saturn warranty on my new vehicle, should an unrelated failure occur in the same circuit. See disclaimer at end of this article.
The following describes my work-around method to install a disconnect switch in the IGN 1/4 fused line, thus obviating the need to remove that fuse every time I tow my Saturn. My method DOES NOT alter the manufacturer’s wiring in any form, thus it should not void the warranty (see the disclaimer at the end of this article). Total cost of materials is about $20.00. The work can be accomplished by the average shade-tree mechanic in a couple of hours or so, depending on one’s desired degree of workmanship perfection -- sloppiness is quick; neatness takes a bit longer. My method adds a simple series circuit consisting of the original fuse (slightly modified) in the engine compartment fuse box, an additional fuse of the same rating (30 amperes, in my Saturn), a fuse holder for the added fuse, and a simple SPST (single pole single throw) switch. All parts are readily available at most automotive and/or consumer electronics parts stores. The IGN 1/4 fuse, in the fuse box, provides the connection points for the external circuit, therefore the fuse must be modified. It is altered to allow for connection of two wires to its lugs, then intentionally blown so as not to bypass the added circuit components.
- Obtain the parts identified in the parts list at the end of this article. Note that the switch MUST be rated higher than 30 amps, the value at which the circuit is fused. You don’t want the switch to fail before the fuse blows.
- Locate the fuse box and remove the fuse designated by the manufacturer for removal prior to towing. See your owner’s manual.
- Using a hobby-type electrical grinder, remove the protective plastic from around the tops of the fuse lugs. The fuse in my Saturn has a small hole near the top of each lug. The goal is to remove sufficient plastic from around the hole in each fuse lug to allow a short length (1/4 inch) of wire to be passed through each hole, then soldered to that lug. Solder a length of AWG 14 wire to each lug. For my Saturn I soldered a 10 foot length of wire onto each lug.
- Strip about 1/4 inch of insulation from the free end of each wire. With the fuse and wiring clear of the vehicle hold one wire’s free end on the negative (-) terminal of the battery. Momentarily touch the other wire’s free end to the positive (+) terminal of the battery. Doing so will cause the fuse to blow. Examine the fuse visually to ensure it is blown.
- Using the grinding tool, cut a narrow slot in the rear end of the vehicle’s fuse box as needed to allow for the wires to exit the fuse box without being crushed when the fuse box cover is secured in place.
- Use electrical tape to wrap the two wires together over a length sufficient to extend from the blown fuse’s holder in the engine compartment fuse box to the desired location for the new fuse holder and switch, such as next to the steering wheel.
- Insert the blown fuse into its holder in the vehicle’s fuse box and lead the wire bundle out of the fuse box.
Install the fuse box cover.
Note: Adjacent to the new cable’s exit point is an empty fuse holder. I placed a spare 30A maxifuse in that position. In the unlikely event of a failure of the added circuit the “blown” fuse could be removed, along with the wiring connected to it. The spare 30 A fuse could then be installed in the IGN3/4 position, returning the vehicle to its original configuration.
- Dress the wire bundle along an existing wire bundle to the firewall and pass the new wire bundle through the firewall via a convenient opening.
- Determine the desired location for the switch and fuse. I mounted my switch in a project box, modified to accept the switch on one end and the new fuse holder on the other end. I then mounted the project box to the left of the steering column, behind the trim panel above and forward of the driver’s left knee. I initially used hook-and-pile fasteners to hold the project box in place but later added two long cable ties for added security. The switch on my vehicle is somewhat out of sight but can be easily reached while sitting in the driver’s seat.
- Connect one lead from the blown fuse to the switch. Connect the other lead from the blown fuse to one lead on the new fuse holder. Connect the other lead from the new fuse holder to the other side of the switch. Mount the switch and fuse in their desired location(s).
- Use plastic cable ties, as desired, to secure the new wire bundle to an original wire bundle or to some other part of the vehicle.
- Insert a new fuse in the new fuse holder. Ensure the new fuse is identical to the rating of the now-blown fuse in the fuse block.
When you are ready to tow your vehicle, instead of pulling a fuse all you have to do is throw the switch. Before towing, don’t forget to perform all other checks recommended by the manufacturer in the owner’s manual. When you reach your destination and prepare to unhook your vehicle, don’t forget to return the switch to its normal position. If you do not, the engine will crank but will not start.
I have not discussed this modification with any Saturn representative. Therefore I do not know Saturn’s position relative to any warranty issues which might be raised by this added electrical circuit.
- 1 fuse, 30 amp Maxifuse Littlefuse part number OMAX030.XP (PEP Boys; $2.49)
- 1 switch, 35 amp, Calterm part number 41770 (K-Mart; $3.89)
- 1 fuse holder, Maxifuse High Amp Fuse Block (60 amp), Littlefuse part number MAB 1BP (Pep Boys; $6.99)
- 20’ primary wire, 14 gauge, Conduct Tite part number 113245 (PEP Boys; $2.69)
- 1 project box (optional item, to house switch and new fuse/w holder) 4” x 2” x 1”, Radio Shack part number RS 270-1802, $2.29. (It’s small but requires considerable modification (removal of plastic screw posts for clearance to accept the switch at one end and the fuse/w holder at the other end.)
- Electrical tape
- Plastic cable ties
- 4 insulated terminals for 14 gauge wire (to attach wire to switch)
- 3” fastener, hook-and-pile, adhesive-backed (for mounting optional project box)
- Grinder, rotary, hand-held hobby-type (e.g., Dremel Mototool)
- Common hand tools
- Soldering iron and solder