Subaru Dash Swap Guide

Subaru Dash Swap Guide

Apr 15, '21

Subaru Dash Swap Guide

DISCLAIMER! WARNING! ALERT! For those who have a dash swap, we are not trying to pick on you. We understand there are many reasons why people would do it, but we have our reasons for why not. iWire has wired GC swaps in every imaginable way and based on those experiences we have come to the conclusions below.

For the love of all things Subaru, please DO NOT dash swap your GC! It is not plug and play! There will still be lots of splicing and modifications needed. Trust us, we get A LOT of calls about this!

If the only priority is to get the car running, then the dash swap could be the right choice. However, if standard car features are important like headlights and taillights, air conditioning, being able to lock the doors, open the windows, and airbags to work in case of an accident, then DO NOT DO A DASH SWAP. It will take more time to get all of these systems working than if the original dash is kept in the car and the ECU to engine section is modified for the new setup by doing a standard harness merge.

Why do people do dash swaps?

Online forum posts make it seem like doing a dash swap will be cheaper, less work, and get the project done quicker than doing a harness merge. In reality, to do the dash swap right with all components functioning like they do from the factory is more work, more expensive, and will take longer than to do a merge. When using the stock dash and doing a merge there is only one section of the harness (ECU to engine section) that is modified compared to a dash swap where you have to modify not only mechanical things like cutting holes in the firewall, modifying the surrounds of the dash as well as modifying the dash bar itself, you also have to modify almost the entire wiring harness.

iWire compared to DIY

Many of the issues we have with the dash swap are the differences between the work we pride ourselves on and the realities of DIY. We will not produce something that doesn't meet the standards we have set forth both in functionality and fitment. With those standards in mind, we have not seen a good way to meet them with a dash swap.

On the other hand, if the car is being built as a side project in the driveway by the owner (IE "because racecar") the standards are very different. Maybe it does make more sense to toss the turbo harness in the car, wire up a fuel pump and fire it up. We wouldn't recommend it, but also understand sometimes it's just the reality of the situation.

Increased Project Scope

With a dash swap the amount of work for the project goes up dramatically. First the entire car needs to be disassembled to remove the harness headlights to taillights. Then the new harness has to be fitted into the chassis it was not designed for. From there cutting, grinding, and welding are required to get the HVAC boxes to fit, then the dash bar to fit, and then trimming the dash itself to get it to fit with the chassis. With all of these added steps, it will take much more time to get the car on the road.

None of these modifications would be required with the stock dash. Simply remove the dash, pull the bulkhead harness, have us merge it, and plug it back in exactly how you pulled it out.

Systems that will need to be wired with the dash swap.

  • High Beams x2

  • Low Beams x2

  • Turn Signals x2

  • Corner Lights x2

  • Fog Lights x2

  • Side Markers x2

  • Wiper motor

  • 2 to 4 doors depending on the model that include

  • Speakers

  • Power Windows

  • Power Locks

  • Side view mirrors

  • 2 to 4 door switches

  • Map Light

  • Sunroof

  • Gas tank (if newer tank isn't swapped as well)

  • Brake Lights x2

  • Reverse Lights x2

  • Turn Signals x2

  • Rear Clearance Lights x2

  • License Plate Light x2

  • Rear wiper and washer (wagon)

This may not seem like a lot, but the quick math of just the number of wires in these systems assuming a 4 door is approximately 150. It ends up being closer to 300 splices because many of them require extensions and splits to multiple locations.

Systems that will need to be wired up with keeping the stock dash

  • ECU

Yes the ECU is a more complex system than the power windows, however, it's only one system to worry about. Despite the added difficulty of the ECU wiring, there are half the total number of wires in the ECU system than all of the systems that have to be wired up with the dash swap and they are all in one spot. By sticking with the stock dash, the best part is that the rest of the car just works by simply plugging it in.

Problems that arise during a dash swap:

1. Routing/Fitment - Routing the wiring harness becomes extremely difficult to do right. Keep in mind an 02+ harness is easily twice the size of 93-01 harness. In addition, the routing between the models is totally different. Think about how the harness flows through each area, how the harness bends and connects, and the mounting points change between each car. So now much of the wiring loom has to be torn apart and rebuilt to get each section routed properly and then mounted up to the car so the harness is secure. All of this has to be fabricated instead of just utilizing all the original mounting points and plugging it in.

2. Creature Comforts - Getting everything to work is a serious chore. As noted above, it may not seem like a lot of systems are left over once the dash is swapped, but there are and it'll be the things that drive people the most batty when they don't work. To add to it, many wires need to be extended and routed across the car for things like side view mirrors or to convert from HID headlights to standard bulbs. So not only are more wires involved with the dash swap than a harness merge, each one takes more time than just making a basic splice.

3. Safety - Airbags are calibrated for whichever car they are in. By swapping the dash, the airbag system is not in an application is was designed for, not to mention that there is no way the dash and dash beam are secured as well as they were in the original chassis. This means that during an accident the airbags may explode a split second too early or a split second too late which is very bad news. If safety is a concern, do not do a dash swap.

4. Aesthetics - We can't really argue the dash swap on the aesthetics of it because everyone has their own opinion. However, we can contend that fitment is never perfect and that is a concern for us. Yes. most of the gaps can be addressed if enough time is taken to sort them out, but there will always be issues with gaps between the doors and pillars.

5. Cutting/Grinding - Getting all of the HVAC to work requires putting new holes in the firewall for the newer style heater and blower boxes. It's difficult to get these holes right and make sure that cabin is sealed from the elements in the engine bay. Keep in mind that if the original dash stays in the car, all of HVAC system plugs back in works just as it did before.

6. ABS - If this is a feature that is desired and the swap donor is from 2005+, it will require swapping the ABS pump and lines from the donor into the older chassis. Although the pump bolts in the lines are designed for a newer chassis and do not fit all that well and leads to another increase in scope of the project.

7. Coupe, 4 Door, and Wagon Differences - If the original chassis does not match the donor then it will create problems. For example if the swapped car is a wagon but the donor is a sedan, none of the rear hatch features will function properly. For those with a coupe, yes there are two sets of doors plugs that won't get used, but that means more modifying of the turbo harness and extra items that are just floating around in the car if they are not removed properly.

8. Door Cards - For models 97 and older the door cards will have to be remove and replaced with 98-01 models that will allow the door to close with the newer dash. This also means swapping out the wiring, brackets, and switches to match which these days are not easy to find.

All in all, there is a lot of work needed to do a dash swap in your Subaru. In some cases it "gets the job done" but for the common Subaru driver we DO NOT recommend doing a dash swap.