Making Turn Signals Louder

Dave and Helen Damouth www/

Revised 5 December 2009

Problem:  Many RVers have reported that they often forget to cancel their turn signal because the audible signal is not loud enough.   This can be because of impaired hearing, high ambient noise, or a flasher module that is mounted far away from the driving position. 

Solution:  This topic has been discussed in several RV Internet forums, including RV-Talk and Diesel-RVs.  Several solutions have emerged.

  1. Both my 2002 Winnebago Motorhome and my 1996 Dodge RAM have a 2-prong signal flasher. I unplugged the flasher and soldered about six inches of insulated wire to each prong, with the connections up against the base of the case, where they wouldn't interfere with plugging the flasher back into its socket. (Use the minimum heat needed to solder, so as to avoid damaging the internal parts of the flasher.)

    Radio Shack has several kinds of 12-volt electronic noisemakers (beeper). I bought the smallest and cheapest, for about $3.00, and soldered the wires from the flasher to the two contact pins on the beeper. (Note that the 12v. positive wire from the flasher (as measured with your multimeter) must be connected to the noisemaker pin marked "+"). After wrapping the connections of the noisemaker with electrical tape (heat-shrink tubing would be neater), I plugged the turn signal flasher back in, letting the noisemaker dangle by the wires.   After verifying that it works satisfactorily, the  beeper can be supported by taping or tiewrapping it to the flasher or some other nearby object.  If the flasher is remote from the driving position, simply run longer wires and put the beeper in any convenient location where it's easy to hear. 

    This works fine - a loud beep synchronized with the turn signals. It's too loud for me - I put a piece of tape on the vent hole of the noisemaker to quiet it down.  I found that if the vent hole is entirely covered, the beeper is almost silent - it takes a little experimentation to get just the right loudness. A better solution would be to place a miniature potentiometer in series with the beeper, allowing an easy adjustment of the voltage applied to the beeper, and hence the volume. I haven't done this, but I suspect that about a 250 ohm potentiometer would provide a suitable adjustment range for most small beepers.

    This solution will also work with 3-prong flashers, but you will need to use a voltmeter to determine which two of the three pins to connect to the beeper

    Newer Dodge trucks (2000 and later) apparently have a 5-prong flasher. I suspect the same solution may work, with the additional complication of figuring out which two pins should be connected to the noisemaker. A  voltmeter should show that voltage between two of the pins is alternating between zero and 12 v. when the turn signals are operating. (Or better yet, look at the wiring diagram in the service manual for this model.) It may turn out that the left and right signals are connected to different contacts of the  flasher, in which case a pair of diodes would be needed connecting two flasher contacts to the single noisemaker input (noting the proper polarity for the diodes).  Small diodes are also available at Radio Shack.  I'd appreciate hearing from anyone who has successfully used a beeper with this 5-prong flasher.

    Other late-model vehicles may have electronic rather than mechanical flasher modules with various numbers of pins. Some of these devices control both the turn signals and the emergency flashers. I have heard that connecting a buzzer across some types of electronic flasher may cause the flasher to operate improperly. In such a case, go to solution 2, below, which is guaranteed to work with any type of flasher.

  2. Buy the Radio Shack beeper and a couple of diodes (also from Radio Shack - any small diode rated for at least 15 volts). Find the wires going to your left and right front turn signals and tap a wire from each light. Run each of the two wires back through its own diode to the beeper in the cab. The diodes must be oriented with the positive end toward the light wire, and are needed to isolate the lights from each other; otherwise, both bulbs will flash when you signal a turn.  My beeper only draws 7 ma., so any small diode rated for at least 15 volts would be adequate. The negative ends of both diodes go to the plus side of the beeper.  The negative side of the beeper must be connected to chassis ground. 

  3. If you have a motorhome built on a Freightliner chassis newer than 2004, with the new MMDC (Multi-module Data Computer) wiring, you'll find that there is no turn signal flasher, and in some brands, the turn signals are completely silent. Solution #2, above, will work fine. Here's a nice article with photos that will help you find the turn signal wires, behind the dashboard.

  4. I recently noticed that Checker Auto Parts stocks an inexpensive 2-pin turn signal flasher labeled something like "extra loud".

  5. Buy a product called "Turn-Alarm". They offer models compatible with standard 2- or 3-terminal turn signal flashers, and also a "universal" model that will work with any type of flasher and does not require access to under-dash wiring. These have an integrated sound generator which beeps when the turn signal is on.  For details, go to

  6. Here is a 2-pin flasher for $8.95, advertised to be loud and musical. In should work in any vehicle that has a 2-pin flasher J.C. Whitney Loud Flasher

  7. Use a mechanical amplifier.   Epoxy a small (empty <g>) catfood can to the top of the original flasher housing. Some vehicles may not have enough space around the flasher to allow this solution.

  8. For relatively new vehicles, contact the dealer and explain the problem.  Chrysler Corporation, and probably other major manufacturers as well, assist their dealers in providing vehicle modifications (often at no cost) to help those with physical disabilities such as a hearing loss.  Another example is that Chrysler provides free seat belt extenders for unusually large people.
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