Acura RSX (DC5): S2000 Push-Start Button Installation
Introduction
This guide covers adding a Honda S2000-style push-start button to a 2002-2006 Acura RSX (DC5), including the Type-S. The button does not replace the ignition key: you still insert the key and turn it to the ON position so the immobilizer is satisfied, then press the button to crank the starter instead of twisting the key all the way to start. Electrically, the button drives a small automotive relay whose contacts briefly bridge the starter (crank) wires at the ignition switch, reproducing the momentary key-to-start action. The result is a factory-looking push-button start that still works alongside the original key. Decide on the button's mounting location before wiring, since several dash positions work and each changes how far the leads must run. Read the follow-up discussion carefully: the simple single-relay approach leaves some ignition circuits live during cranking and can stress the accessory (radio) circuit, so review the warnings and consider the two-relay refinement raised by later posters. Adapted from a community writeup by KSMatic on Club RSX (https://www.clubrsx.com/threads/diy-guide-how-to-install-s2000-push-start-button-visual-guide.389791/), including corrections from the follow-up discussion.
Reference
Tools Required
- Wire cutters and wire crimper
- 16-18 gauge stranded wire (about 4 feet total)
- Female spade connectors or insulated wire taps
- Electrical tape or heat-shrink tubing
- 12V test light or multimeter
- Screwdrivers and trim tools for the steering column and dash panels
Parts Required
-
S2000-style push-start button with its 3-pin lead (green = output/trigger, red = power, black = ground)
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Automotive 12V 30A SPDT 5-pin relay (terminals 30, 85, 86, 87, 87a)
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Mounting bezel or blanking panel (custom-molded, JDM, or an existing switch opening such as the hazard or power-mirror location)
Safety Warnings
- ⚠ Use an SPDT 5-pin relay, not an SPST 4-pin relay. The two are wired differently and an SPST will not switch this circuit correctly.
- ⚠ Single-relay caution: this method bridges the battery and starter circuits but leaves the ACC and IG2 circuits live while the key is ON. Per the RSX service manual, ACC and IG2 should drop out during cranking; with one relay they do not, so a voltage spike can reach the accessory line and damage the radio. Later posters recommend a two-relay version that isolates those circuits for a correct install.
- ⚠ Tap the correct ignition leads. One installer wired into the wrong wires and the clutch switch then cranked the starter every time the pedal was pressed, even with the key removed.
- ⚠ Insulate every connection. Exposed joints can short; if a circuit blows, replace the ACC fuse.
- ⚠ This is live 12V work near the steering column. Disconnect the battery before tapping wires to prevent shorts and accidental cranking.
Step-by-Step Instructions
1 Remove the lower steering column trim
Disconnect the battery so you are not working on live 12V wiring. Take off the plastic shrouds around the steering column to expose the ignition switch and the harness that sits below the key cylinder. This is the area where the starter (crank) wires are picked up.
2 Locate the ignition harness and identify the crank wires
At the ignition switch, find the brown 8-pin connector (KSMatic marked his with blue tape to spot it). The two leads you need are WHITE and BLACK/WHITE, which carry the crank signal. One later reader recalled a black/yellow wire, but the writeup author reconfirmed the correct pair as WHITE and BLACK/WHITE. If unsure, back-probe with a test light while turning the key to the start position to confirm which lead goes live during cranking.
3 Run trigger leads to the button location
Run two lengths of 16-18 gauge stranded wire, roughly 20 inches each, from the WHITE and BLACK/WHITE ignition leads out to wherever the button will sit. You can tap into these wires rather than cutting them completely. Choose a wire gauge that matches the lead you are joining to.
4 Choose and prepare the button mounting location
Common spots are the cigarette-lighter surround, the driver-side control panel, the hazard-switch opening, or the round power-mirror switch opening. One installer fitted the button into the power-mirror switch hole for about $47, enlarging it a little at a time and beveling the edge with a sharp razor for a near-OEM fit, then relocating the mirror switch to a hidden panel. Avoid a location a front passenger can bump, since an accidental press can crank the starter while driving. A custom bezel is usually needed because the JDM right-hand-drive bezel does not suit a left-hand-drive RSX.
5 Tap switched power and ground for the button
Source the button's own 12V supply and ground from the cigarette-lighter harness. On that plug, YELLOW/GREEN is positive and BLACK is ground. Remove the cigarette-lighter panel to reach these leads, then run the power and ground out to the button location alongside the trigger leads.
6 Wire the relay contact side to the crank wires
Connect the two ignition leads (WHITE and BLACK/WHITE) to relay terminals 30 and 87. The order between these two is interchangeable. When the relay closes, terminals 30 and 87 are bridged, which momentarily joins the crank wires and turns the starter. Use a 5-pin SPDT relay; terminal 87a is left unused.
7 Wire the relay coil to the button trigger
The relay's coil terminals are 85 and 86. Connect the button's output/trigger lead to terminal 85. The author's original notes label this the green wire; in a later clarification, working from his own unit, he identified the trigger lead as the yellow wire, so trace your specific button to confirm which color it uses. Connect terminal 86 to ground; splicing into the button's ground lead is an acceptable way to do this. Pressing the button then energizes the coil and closes the contacts wired in the previous step.
8 Connect the button's power and ground
On the S2000 button, the red lead is power and takes the 12V you tapped from the cigarette lighter, and the black lead is ground. The button's ground can share the same ground point used for relay terminal 86. With power, ground, and the trigger lead landed, the button is fully wired.
9 Insulate, test, and finish
Tape or heat-shrink every joint so nothing can short against metal. Reconnect the battery, insert the key and turn it to ON, then press the button; the starter should crank and the engine start. If nothing happens, recheck the fuses (including the ACC fuse), confirm the relay terminal assignments, and verify the crank wires were tapped correctly. Once it works reliably, reassemble the trim panels.
Pro Tips
- 💡 The button only cranks the starter. The key must still be in the ON position with the immobilizer satisfied. If the key is only at accessory, pressing the button will crank endlessly without the engine catching.
- 💡 Do not defeat the immobilizer. One installer who disabled it could hear the starter turning but the engine would not run.
- 💡 After any power interruption the radio may display CODE. Have the anti-theft code ready (Acura supplies it on a card in the owner's booklet) before finishing.
- 💡 A 16-18 gauge spec means any wire within that range is fine; matching the gauge of the existing wire is best.
- 💡 The relay is a standard automotive 5-pin unit sold at electronics and parts stores; genuine buttons and plug-and-play harness kits are also available.
- 💡 Mounting the button where the hazard switch or power-mirror switch normally sits gives the cleanest, most OEM-like look.
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