Super easy upgrade for brighter, safer and more reliable headlights

[AdamB]

The performance of the headlights on my Airstream Cutter have been getting worse and worse since we bought it almost two years ago. The lights were working when we bought it, although they were quite dim and I thought that I would need to replace the headlights with some higher performance ones. The problems started with the headlights flickering occasionally during a road trip down south about a year later. But the flickering was so rare that I thought I was just “seeing things” and we just didn’t use the lights very often so I forgot about it. Early last year the headlights just stopped working altogether. The switch was fried. I replaced the headlight switch and thought the problems were over. Then the headlights started going out again on the way to the fall Air Forums North California Rally at Jackson Rancheria last October. The new headlight switch was burning hot as the thermal cutoff was working to keep the switch from melting (by cutting off the power to the headlights). We got into the RV park before it was totally dark..... but I had to pull over twice for 10-15 minutes to let the switch cool off and get the lights back on.

After consulting AirForums and IRV2, I found Daniel Stern’s website which explains the problem. He provides some very helpful diagrams and sells parts and kits for this upgrade. The problem is basically that the headlight switch is taking all the power to all of the lights directly (which overheats the switch), wiring that is too thin and lack of a relay. There was no relay installed by Freightliner at the chassis factory (Here’s a good explanation of how relays work). The switch (and a lot of the 12v wiring chassis) selected by Freightliner are manufactured by Ford. That particular switch was used on Ford pickup trucks from the early to mid 1980s. My motorhome has 6 taillights, 12 marker lights, 2 low beam headlights, 2 high beam headlights and 2 front turn signals that are always on when the headlights are on. That’s 22 lights when the low beams are on and 24 when the high beams are on (and even more when turn signals and brakes are factored in). Add in the lights from towing a trailer or toad and we’re looking at 30 lights going through the switch and wiring. I don’t think that any of these Ford trucks had even half that amount of lights going through that same switch. It’s easy to see that the switch is being asked to do a lot more that it was designed for in the first place. This was probably acceptable when the vehicle was new. Years of use and age degrades the components involved and they eventually show their weaknesses.That’s when problems arise.

I had volunteered a week ago to drive the guys from work in the motorhome to our annual trip to see the San Jose Sharks hockey game. A few days before the game I remembered that I better take care of this issue quick. We would be coming back from the game in the dark, so I had to at least get the low beams upgraded. I bought the fuse holders (w/30 amp fuses), wiring (12 gauge) and the crimp connectors from my local West Marine store. These are all marine grade components manufactured by Ancor Marine. I got the relays (40 amp) and relay holders from an electronics supply shop. The cost for all this was less than $100US and I’ll be spending a little bit more in the future as I improve things further. I followed the wiring harness from the headlights to find the wire bundle leading to the light switch. Then I consulted the wiring diagram in my motorhome owners manual to find which ones in the bundle were low and high beam wires. I was fairly sure I had the correct wires identified, so I just cut the one identified in the wiring diagram as the low beam. Then I turned on the lights and all the markers and tail lights turned on, but not the headlights. So I had found the correct wire to splice the relay into. Then I disconnected the ground (-) wire from the chassis battery. There are four connections for the relay: positive 12v, negative ground, signal from the switch (which I had just cut) and the other side of that wire going to the headlights. The procedure was actually quite easy. I found the solenoid under the front hood that had a very thick 12v cable coming from the battery compartment. This power point is hot at all times and is used to power the blower motor for the heating and a/c as well as the wipers, etc. I used an existing ground to the frame for the grounding point. I took both of these parts apart a bit and cleaned up everything with electrical contact cleaner. Then I put everything together using heat shrink tubing to cover up all the splices. I used a zip tie to tie down the relay. Then I reconnected the chassis battery. I decided to wait on upgrading the high beams until after I observed the performance of the low beam upgrade.

Here are some before and after photos of the low beam relay upgrade:







These pictures were taken with the motor off at the height of the afternoon on a real sunny day. The difference is night and day!

Here’s a picture of the wiring:





It was dark after the game ended last week around 10pm. The lights were indeed brighter than ever and they stayed on for the entire one hundred mile ride home. The headlight switch was warm by the end, but not scalding hot like before. I don’t drive the motorhome at night very often, but it sure was nice having enough light and reliable light for a change.

What I did not upgrade was the headlights, headlight sockets, or the wiring going from the relay to the headlights. So before I upgrade the high beams with a relay, I’m going to obtain these parts first as well as a weatherproof relay holder so the upgrade will be heavy duty and look more professional. Freightliner used 14 gauge wire for the headlights which is not thick enough, so I will be upgrading the 12v wires from the relay to the headlights to 12 gauge marine grade wiring.

I did upgrade my front amber marker lights to LED units last winter primarily to stop water leaking in from them, but also to reduce the load on the light switch and wiring. I will upgrade the 5 red rear ones as well soon. I’m also considering replacing the tail light bulbs with LED bulbs as there’s no LED tail light enclosures available for my particular tail lights. I’ll also be upgrading my battery cables, cleaning all the ground connections all other 12v chassis connections with contact cleaner and/or replacing components where needed. Right now my cruise control, horn and driving lights are non-functional. So I’m looking forward to getting those electrical problems solved soon.

I’m not sure what Airstream motorhomes do not have headlight relays installed at the time of manufacture, but I would guess that most models up to the late ‘90s (at least) don’t have them. This upgrade is very common for any car that didn’t have a relay installed as part of the factory wiring harness. Here’s a video of a guy doing this upgrade on a ‘77 Dodge truck. He decided to use circuit breakers instead of fuses on his upgrade. For safety’s sake, I highly recommend that everybody with an older motorhome perform this upgrade if their motorhome doesn’t have a relay already installed. Any older vehicle can benefit from this upgrade as well. I know a lot of you have already performed this upgrade, but I bet a lot have not done it. So if you didn't do it, it's super easy and a big bang for the buck. I did it in less than an hour. You can read on Daniel Stern’s site about how voltage loss affects light output... but the proof is in the pictures.

[masseyfarm]

Good detail on the upgrade Adam.

On your driving lamps, they are probably also tied to the headlamp circuit which just adds to the load.

I have separated them also with a relay to a independent circuit
.
http://www.airforums.com/forums/f313...ml#post1003514


Dave

[AdamB]

Thanks Dave! I know it was long-winded... i shouldn't have had that extra cup of coffee yesterday! That post of yours helped me to find the correct switch last year.

Anyhow, I'm kinda thinking of starting a "sticky" FAQ for 1990s Airstream pusher motorhome owners that would list common potential problems and solutions. It would include parts suppliers, upgrade ideas and workarounds for obsolete parts. Could even be a wiki.

Any thoughts on using LED bulbs in your tail lights? It seems like a no-brainier and the flasher unit may or may not need to be upgraded.

[idroba]

My only additional suggestion is to carry at least one spare relay (assuming the ones you use are all the same). I relayed the lights on a car I owned once, and unfortunately the low beam relay failed one night, leaving me with only high beams. I was too stupid to remember I could swap out the hi and low relays, so had only hi beams. I annoyed a lot of folks that evening.

Point is, relays do fail so have an extra on hand. Real critical if you relay the tail/running lights too.

[is.chowa]

Adam, very good project and explanation. Found your link to Daniel Stern’s website to be very informative. Am in the process of doing mine and have completed one side will finish to-day for the other. I am using 4 relays, 2 for each side (Low/Hi beam) and redid the ground connections to eliminate the short splices that were there. I will post pix of the project when complete. The grounds were a horrible mess and the light wires originally used (inadequate) were replaced with #12 guage, this includes the ground and 12V power sourced at the battery thru fuses.

Thanks for doing the work and posting your process. It made my project a lot easier.

Steve