2nd Gen Non-Engine/Transmission Rheostat for guages

[rweis]

I am going to put 2 dual gauges in a pillar 3 gauge holder. I am thinking of puting a rheostat to control the lighting in the 3rd gauge space and fusing it to a line that is powered when the headlights are on rather than trying to tie it to the instrument panel lighting. I am thinking that the lighting in the pillar should be independent because you may want more or less light on the pillar than the regular instrument panel.



I think I can find a 10 watt rheostat at Radio Shack and that should be pleanty.



I don't know much about vehicle wiring, but figuer I can find a circuit in the fuse panel at the end of the dash that will suffice.



Am I missing something here? I have not seen this kind of a setup in any of the threads, and am thinking maybe there is a good reason I have NOT seen this setup in the search engine.

 

[illflem]

Your idea is an excellent one, don't know why no one else has mentioned it. My only suggestion is that you mount the rheostat in a location where the heat from it won't cause any damage, the pillar probably wouldn't be a good spot.

 

[M Barnett]

When I installed my gauges, I used the wire from the headlight switch so the gauges dim with the dash lights.

Michael

 

[OL RATLR]

gauge dimmer

rweis! I found with my Isspro gauge and bulb

covers you probably wouldn't need a dimmer

although I have them wired with dimmer.

OL Ratlr

 

[BatMan01]

rweis

I have been thinking about this one for a while know. I installed mine and tapped off the the headlight switch. I do not remember off hand which wire I tapped but it does allow me to control the lighting through the instrument panel control. I also put a switch in line so when I do not want the extra light at night from the a-pillar I just turn off the switch and off they go. This is just temporary because, like you I want to have more or less light than the instrument panel not on or off. My idea is to use a circuit with a relay. What I am thinking is that with the tap that I am using from the head light switch and 12v pulled from the fuse block with a reostat in-line then I will have what I want. When the lights are turned on the relay would be enginergized completing the ciruit from the the fuse panel giving me a full 12 volts to the reostat to light my a-pillar guages. This will also put less load on the light switch. I hope to put this together in December when I get time. Just An Idea. I hope this helps.

 

[rweis]

Batman - EXACTELY



The idea is to have gauge lighting independently controlable from the instrument panel rheostat, but will be on when the lights are on ie the relay connected to the light switch. Also in talking to the diesel mech at the dealership he warned about loading the existing dimmer control and screwing up the instrument panel cluster.



With the seperate rheostat you could adjust the pillar lighting at will when ever the main headlight switch is on and without pulling it through the instrument panel rheostat.



I do not know a lot about vehicle wiring, can keep the hot side away from the ground, lol. I like the relay idea. Something with a small close current and then feed that with the fused 12 volt. I am thinking of taping the power seat fuse (I do not have power seats) for the power source since that is always on (as I understand it) but would need to have an idea of what wire color / trace I am looking for. It has to be close to that fuse panel and then go down under the carpet to the seat.



I was going to mount the rheostat in the pillar, but have had second thoughts about that due to heat disipation. I am now thinking of mounting it in the knee panel to the left where the flat part of the contour is left of the seam that is left of the steering wheel. Sort of directly under the existing light control and straight down to the knee panel.



Should be room to mount the relay there as well.



I am planning to put 3 dual gauges in the pillar and 1 or 2 or 3 in a dash mount. The gauges are Westach electricals. The pillar egt/egt (pre, post), oil pressure / oil temp, trans temp / trans temp (pre and post cooler). The dash mount boost / fuel press ? I have called Westach twice and asked them if they have that combination, but "we'll get back to you" has not happened yet. If they do not have the dual then single boost and fp. Eventhough not bombed yet I was going with the 50# boost and the 30psi fp. Could easily have a different lift pump within a year or so.



As the 3rd gauge in the dash a trans pressure, but not sure where to get the sensor placed and not sure I would know what the different readings would tell me. I read a post about what different trans pressures are doing at different functions and will have a blank hole to put it in. Could also put a hourmeter there and that would make sense and help with maintenance changes.



Where are you going to get the relay? Radio Shack?, NAPA?, JC Whittney? and what kind and size for latching current and contact current?



Thanks for the reply



Bob Weis

 

[illflem]

Bob, I would skip the relay and just pick up power from a circuit that is only on when the ignition is on, cig lighter comes to mind. No big deal if the gauge lights are on when the headlights are off. If you decide to mount your rheostat in the knee bolster make sure to use quick disconnects or a plug. I can't begin to count the number of times my bolster has been removed for one reason or another. I gave up the idea of mounting anything on it for that reason. I found plenty of room in my '95 for switches in the bottom steering column cover, not sure on your year though.

 

[BatMan01]

rweis

I have not sat down to figure out the components necessary so I do not know where I will purchase from. As for a 12 volt source I will probably pull it from "Pain-Less" breaker panel. If I did not have that I would pull from the factory fuse panel to keep it simple. I also want the gauge lighting to be automatic when I turn my lights on. This way I only have to adjust the brightness when I need to. For this reason I am going to use a relay and tap off the light switch. I currently have a three guage A-Pillar installed with EGT, Boost and Fuel Preasure. As I mentioned before I have already tapped the light switch and I have a switch in-line to turn off the lighting. This setup works but I would like to have the lights a little bitghter at times when it is dark. I like to have my dash lighting down low at night and this makes my pillar lighting almost off. This is on of the reasons why I am going to build this circuit with the reostat. The other is to take the load off the factor light switch.

 

[rweis]

I went looking for a 12 volt relay that takes little power and is NO (normally open) ie off. I found several in my MOUSER (major national electronis parts supplier) catalog.



I started trying to figuer out what kind of wattage the rheostat would take and what was available at a reasonable cost. First we need to figuer out the resistance size needed (ie a range for dimming). E=I*R great theory, but what is practical? I find most of the reasonable prices rheostats are in the 1 - 2 watt size. I am not sure this will give enough heat disipation. The larger wattage sizes start getting pricey and larger in size fast. I was thinking on the way home about using a 7 position selector switch ($1. 50) and some fixed 5 watt resistors (about . 25 each). Would give good heat disipation simple (the wire wound variable rehostats often get dirty and start being scratchy (like a scratchy radio volume control knob)). Still simple, fixed, cheap, 7 (you can get the selector switches with as high as 12 positions) different lighting levels (one could be off ie NO resistor, one could be full 12 volt ie full bright) Still have to experiment a little to see what size reistors to use.



The comment about having the thing on a disconnectable plug is a good idea.



I still like the idea about the relay using the headlight switch to close the NO (normally open) relay to keep the load off the instrument cluster system. I also run with my panel dimmer control set to the absolute minimum level (minimum inside lighting gives you maximum night vision). This is why I think the guages should have a seperate dimmer, they are in a different place and should be seperately controllable.



So where are we?, a small normally open relay (btw the contact capability of the small relays is 6 amps, like huge pleanty) the relay takes 17 milliamps to operate (like almost nothing) about $3, and about $5 in a 7 position switch (self cleaning) with fixed resistors, and a 2 pin plug ($1. 50). Control, simple, 1 moving part, stay out of the factory dash system. I think I like it

 

[Big White Beast]

Why adjustable........

While I agree that separate dimming is a good idea, why not just find a comfortable level and put in a resistor to drop the lighting level. I can't think of why you would want to adjust it. Same with my dash lights. Once set I never adjust them again.



As far as the resistor start at the 100 ohm range. That should drop you to about 5 volts from 12 V, remember that were probably running closer to 14 volts than 12. If that's too dim go lower to 75 ohms or so. I would go with a higher wattage resistor to compensate for the heat it may generate.



Just my 2¢ worth,



Garrett

 

[JJW_ND]

Caution on the lights on all the time.

I had my Westach gauges wired direct to the ignition, on with the key. After four years and several bulb changes (one for each gauge) I final took the time to wire into the headlight circut. You will really wear out bulbs if they are on day and night.



I can't imagine piller mounts are very easy to change bulbs!



jjw

ND

 

[dpost]

Re: Caution on the lights on all the time.

Originally posted by JJW-ND

I had my Westach gauges wired direct to the ignition, on with the key. After four years and several bulb changes (one for each gauge) I final took the time to wire into the headlight circut. You will really wear out bulbs if they are on day and night.



I can't imagine piller mounts are very easy to change bulbs!



jjw

ND

The advice illflem gave sounds good to me. Remember the KISS principle (Keep It Simple Stupid). Adding a relay is not necessary for the small amount of power needed for two small bulbs. Your first posting, with the dimmer mounted in one of the gauge openings sounded like a winner.

 

[JBlock]

Isopro bulb covers

I agree with "OL Ratlr" I had my isopro EV on the dimmer switch and they were had a bright reflection on the windshield. I have a center pod. I added the color covers in green tint and the guage are perfect now. the temperature guage with the color face did not require a color cover. -- email address removed -- furnished everything. He a good gur I recond working with him.



Joe

 

[Dr.Kayak]

If you have Autometer gauges yow will not need a dimmer. They are very Dim already. I wired in a small switch so I can turn off all gauge lights on the A-pillar. Mine are so dim that I rarely turn the lights off.



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[jbone]

Guys, like most just tied lights to adjustable lights in dash, thought about them being to bright, but they are not--I would test them out before doing all that wiring--unless that is your idea of a fun saturday afternoon... ... ... ... R, J. B.