Moparts
Dim and Bright lights in the dash
Posted By: cornet684me
Dim and Bright lights in the dash - 11/11/10 06:40 AM
i have a 68'dodge coronet , i was told that there is a way to wire a wire from the alternator to the battery to stop the dim and flickering lights in the dash, when the car is at idle, the dash lights are dim, when i give the car gas, the dash lights and all the lights get brighter, does anybody know the trick to getting brighter lights at all times?
Posted By: Swiss_Robert
Re: Dim and Bright lights in the dash - 11/11/10 10:39 AM
There are a number of post from a guy named nachort74 here on the board - he's the guru in my eyes about that...
So the "trick" would be a stronger alternator that can load the battery in idle.
First I would recommend to attach a voltmeter to check voltage at the battery when idling and at about 2000rpm.
(The trick "with the cable" is to fix melted bulkhead connectors at firewall or even ampere-meters - but if you check your battery you will find out if any bad connecitons are your problem)
Posted By: Yancy Derringer
Re: Dim and Bright lights in the dash - 11/11/10 06:07 PM
Mopar did a "bad thing" with wiring in these, especially now that folks want to run stereos, pumps, fans, etc. ALL the high power conductors for the vehicle go through the bulkhead connector, sometimes two or three times, IE Alternator feed comes IN to ammeter, back OUT to battery, then headlights go OUT to lights, etc.
Also it has been alleged that the internal design of the older alternators (round back) are such that they simply do not "put out" much at low RPM.
I cannot personally confirm this, it may be true. You CAN use a newer "squareback" 70/ later alternator on your 69, by grounding the second field terminal.
So a combination of upgrading the alternator and look up the "Mad electrical" articles on ammeters and bulkhead connectors.
If you aren't a "concourse" freak, there are some ways to upgrade the wire size and keep the ammeter. One way is to drill out the bulkhead connector and slip larger wires right through with no connectors on them.
Also, on your dash lights::
Clean grounds, clean the sockets, clean or replace the bulbs. Make sure the bulbs are the recommended part no. There are MANY different bulb wattages of the same bulb size, so if you get a "heavy" bulb in one hole and a "light" bulb in another, you'll have a big difference in brightness.
Dirty, corroded instrument lamp dimmers don't help, either. You can actually reach a situation where as the charging voltage drops, the rusty wiper on the dimmer can start to arc and lose connection. Most of the time you can just twist the dimmer back and forth vigorously to clean up the slider.
Posted By: Sinitro
Re: Dim and Bright lights in the dash - 11/11/10 08:10 PM
Time to kleen the bulkhead connectors..
Unsnap each, wire brush the connectors and apply dia-electric grease. Replace any terminal that is damaged, replacements available from Napa.
Keep in mind...
The electrical systems in our ole Mopars was designed to handle a max of about 40 Amps..
If one has added electric fans, fuel pump, subwoofer amplifier the system need to be beefed up.
Just my $0.02...
Posted By: BDW
Re: Dim and Bright lights in the dash - 11/12/10 01:41 AM
Add a jumper from the alternator to the battery, worked wonders for me.
http://www.allpar.com/history/mopar/electrical.html
Posted By: MO_PA
Re: Dim and Bright lights in the dash - 11/12/10 03:53 PM
After all is said and done put a smaller diameter drive pulley on the alternator.
Posted By: Junky
Re: Dim and Bright lights in the dash - 11/12/10 04:25 PM
Read up on
http://www.madelectrical.com/ how to bypass the amp meter and how to rewire. Install a volt meter. Install a Denso alternator. I did this on my Coronet. No more dim lights.
Posted By: Yancy Derringer
Re: Dim and Bright lights in the dash - 11/12/10 05:52 PM
Quote:
After all is said and done put a smaller diameter drive pulley on the alternator.
Not all that great an idea. "Back when" I was roaring around Sand Diego in my '70, it had the "optional" 60-65? amp alternator. Small pulley ona 440sixpack. After 2 failures, I figured out the ratio. 4:1 !!!!??? This means that when the engine is spinning at 5K, the alternator is spinning.........20,000 RPM!!!!
The windings vibrate inside, and scrape the insulation off "themselves," the little pins that the stator indexes onto in the cases wear, and allow the stator to get out of alignment. In one case, the stator was hitting the rotor!!!
I ran a Delco back then!!! This was 1973
Posted By: Sinitro
Re: Dim and Bright lights in the dash - 11/12/10 06:11 PM
Quote:
i have a 68'dodge coronet , i was told that there is a way to wire a wire from the alternator to the battery to stop the dim and flickering lights in the dash, when the car is at idle, the dash lights are dim, when i give the car gas, the dash lights and all the lights get brighter, does anybody know the trick to getting brighter lights at all times?
First...
Fix the bulkhead connectors..
A bigger alternator and/or pully change will not correct the problem if there are bad, oxidized connections.
Just my $0.02...
Posted By: jbc426
Re: Dim and Bright lights in the dash - 11/12/10 07:14 PM
As many posters have stated, it's a multi-issue problem. It's best resolved addressing the bulkhead issue, the ampmeter issue, upgrading the alternator wiring in both size and routing and if you are running anything more than a stock electrical load, swaping out the Mopar alternator for one of the many replacemnts that have been successfully used. One of the strongest alternators at idle is a Delco-Remy product. Check out this link.
https://board.moparts.org/ubbthreads/show...e=3#Post6295580
Posted By: cornet684me
Re: Dim and Bright lights in the dash - 11/13/10 05:40 AM
hey Wilson, that is the thing i had heard to do that is a simple fix, i read this article you gave me link too, so i run the wire from the starter rely to straight over to the alternator?
Posted By: cornet684me
Re: Dim and Bright lights in the dash - 11/13/10 05:42 AM
i have disconnected the amp meter and connected the wire together under the dash already
Posted By: cornet684me
Re: Dim and Bright lights in the dash - 11/13/10 05:44 AM
i really do not have a major problem, i have replaced all the bulbs, while driving down the highway all the interior lights are fine, the problem is at idle, the interior lights get kinda of dim, however asap when i go back to driving again everything is fine, it is more a personal thing , i do not like the dim lights at idle, so what everyone is saying, the best fix will be changing out the alternator?
Posted By: jbc426
Re: Dim and Bright lights in the dash - 11/13/10 07:04 AM
How many wires does the alternator have on the back of it? (2)One bigger one and one smaller one, or (3)one bigger one and two smaller ones?
If you only have 2, you can buy and install the dual field alternator (3 wire) and that will solve the low rpm pulsing of the lights.
You will want to install a bigger, big wire from the alternator stud to the starter relay. Be sure to use the correct size fuseable link on the end of it at the relay.
Posted By: Yancy Derringer
Re: Dim and Bright lights in the dash - 11/13/10 07:18 AM
There's been some discussion that the older (69/earlier) alternators had a design which prohibited decent low rpm output, and that the later-frame units solved this. So long as your wiring is "up to snuff" AND IT'S not a wiring problem in the regulator circuit, or the regulator itself, you might indeed improve things by swapping up to a later model alternator.
If you want to try it, as noted above, you only need to ground the second field wire.
However, without much additional work, you can add just one more wire, and convert to the '70 and later electronic regulator, as well
Posted By: BDW
Re: Dim and Bright lights in the dash - 11/13/10 02:23 PM
Quote:
hey Wilson, that is the thing i had heard to do that is a simple fix, i read this article you gave me link too, so i run the wire from the starter rely to straight over to the alternator?
It's really that simple. As stated make sure you use appropriate gauge wire with a fusible link.
Posted By: Junky
Re: Dim and Bright lights in the dash - 11/13/10 06:00 PM
Educate yourself by reading
this. Then purchase and install a Denso alternator. All problems solved.
From my experiences, the square back and the round back alternators have the same low idle problems. Not enough output to keep the lights bright.
Take a look at
AndyF's Denso setup.
Posted By: NachoRT74
Re: Dim and Bright lights in the dash - 11/13/10 06:38 PM
Quote:
Educate yourself by reading this. Then purchase and install a Denso alternator. All problems solved.
not agreed on madelectrical solution as many of you know from me.
Quote:
From my experiences, the square back and the round back alternators have the same low idle problems. Not enough output to keep the lights bright.
depending what squareback alt you choose. Stock 78 amps are available fro cheap ( $500 without core return ) and even they are not THE BEST OF ALL ( they are still some unneficient at iddle for the max output rate stated ) but they will solve the problems in the old school Mopar way. They put at iddle around 40-45 amps, what is in mostly of old Mopars the max alt output mounted
But average, yes, round and squarebacks alt are pretty much the same, simply squarebacks are easier to service.
elec or mech regulator is more relate with regulation eficiency not really with alt output, but of course a more efficience reg will result on a better charge capability with less power missing. Then also will save from "electrical noises" on electronic devices.
They mopar alt problem is more related with stator windings design than all the alt itself
Quote:
Take a look at AndyF's Denso setup.
if you don't care about old school mopar look, thats a great solution. If you care, you have 100 amps Tuff Stuff alts assemblied on old kind housings.
Posted By: jbc426
Re: Dim and Bright lights in the dash - 11/13/10 09:06 PM
Quote:
Educate yourself by reading this. Then purchase and install a Denso alternator. All problems solved.
From my experiences, the square back and the round back alternators have the same low idle problems. Not enough output to keep the lights bright.
Take a look at AndyF's Denso setup.
Some good advice, but if he doesn't have any aftermarket electrical load a squarback will be more than enough to stop the low idle issues.
Denso's will work, but aren't much better compared to what's available these days. How about a CS144 with 80 to 115 amps at idle and 140+ just above idle. Bolts on to the stock mount with a $30 adaptor.
Posted By: NachoRT74
Re: Dim and Bright lights in the dash - 11/14/10 08:12 PM
Quote:
Quote:
Educate yourself by reading this. Then purchase and install a Denso alternator. All problems solved.
From my experiences, the square back and the round back alternators have the same low idle problems. Not enough output to keep the lights bright.
Take a look at AndyF's Denso setup.
Some good advice, but if he doesn't have any aftermarket electrical load a squarback will be more than enough to stop the low idle issues.
JUST the right one, not anyone
Posted By: Sinitro
Re: Dim and Bright lights in the dash - 11/14/10 11:28 PM
Quote:
i really do not have a major problem, i have replaced all the bulbs, while driving down the highway all the interior lights are fine, the problem is at idle, the interior lights get kinda of dim, however asap when i go back to driving again everything is fine, it is more a personal thing , i do not like the dim lights at idle, so what everyone is saying, the best fix will be changing out the alternator?
Another basic question..
What is the idle RPM?
The lower this is, the less voltage the alternator will put out..
Just my $0.02...
Posted By: RapidRobert
Re: Dim and Bright lights in the dash - 11/15/10 12:25 AM
Good stuff. Clean all connections including grounds esp the bulkhead in/out or better yet Nacho's simple 2 wire bypass. 78 amp squareback from late 70's iirc (maybe 80's). attach stereos etc to the alt side w relays including the headlights. If want to bypass the ammeter run an 8ga from alt to starter relay protected w a 12ga fusible link and also a FL at the alt output. there's 2 sizes of alt pulleys & I would use the smaller one
Posted By: hooziewhatsit
Re: Dim and Bright lights in the dash - 11/15/10 12:40 AM
Quote:
there's 2 sizes of alt pulleys & I would use the smaller one
I have a squareback alt with a double pulley (78A I believe). The pulley diameter is 3" at the outermost edges. Is there a smaller one available? (Mine has trouble with the headlights at idle, ~750rpm).
Posted By: RapidRobert
Re: Dim and Bright lights in the dash - 11/15/10 12:53 AM
When I was diggin thru my stash I saw 2 sizes but didn't measure either one but I would think yours unfortunately is the smaller one. EDIT pic is much larger (posted) than what it shows on my computer. You can see which one you have
Posted By: 1_WILD_RT
Re: Dim and Bright lights in the dash - 11/15/10 01:23 AM
Apparently no one uses relays on the headlight circuit anymore... The charging system mods are good I'm not arguing that.. But adding headlight relays means the majority of the current to the headlights never sees the bulkhead & the current to the dash lights is suddenly not drawn down by the head light load... Also very beneficial for the heater blower on high speed..
Posted By: cornet684me
Re: Dim and Bright lights in the dash - 11/15/10 01:36 AM
hey Randy, what are you talking about with adding a relay? how wld this be done?
thanks
Posted By: cornet684me
Re: Dim and Bright lights in the dash - 11/15/10 01:38 AM
i have the one with the smaller dual pulley
Posted By: cornet684me
Re: Dim and Bright lights in the dash - 11/15/10 01:40 AM
thanks for all the info Junky, looks like i have decision to be made, i think i am going to try to 1wire 1st and maybe the relay before i go to a full blown mod,
Posted By: landon1
Re: Dim and Bright lights in the dash - 11/15/10 01:54 AM
adding relays made a HUGE difference on my car with the brightness of the headlights. my stock dash lights always flickered a bit, but i don't recall how they acted after adding relays and now i run aftermarket gauges.
Posted By: 1_WILD_RT
Re: Dim and Bright lights in the dash - 11/15/10 01:55 AM
Typically I install a pair of standard Bosch 40a relays in front of the radiator yoke on the drivers side... Open the headlight harness & identify the power wires from the bulkhead to the high & low beam headlights... These are now going to be the control leads for the relays connect them to terminal 86 of each relay.. Add ground wires to terminal 85 of each relay... run a couple 12 gauge wires from the main terminal to terminal 30 add a 20 amp fuse to this wire & finally hook the headlight feeds up to terminal 87 keeping the high & low beams tied to their original feed.... Basically the relays act as the switch carrying the whole load, the original switch & wiring only carries the approximate 300ma load required to trigger the relays.... Adding the same to your blower motor means the blower switch no longer carries the load which often burns out the switch and the blower motor spins quite a bit faster...
Posted By: hooziewhatsit
Re: Dim and Bright lights in the dash - 11/15/10 04:11 AM
Quote:
When I was diggin thru my stash I saw 2 sizes but didn't measure either one but I would think yours unfortunately is the smaller one. EDIT pic is much larger (posted) than what it shows on my computer. You can see which one you have
D'oh, looks like I have the tiny one already. Thanks for posting the picture.
For the headlight relays, my relays came with a plug that holds the wires. I found that the female spade connectors Napa sells for the bulkhead connectors will slide in and lock in place. This mean I have no actual splices in the install. 
Posted By: 1_WILD_RT
Re: Dim and Bright lights in the dash - 11/15/10 04:18 AM
Found a diagram in my photos....
Posted By: cornet684me
Re: Dim and Bright lights in the dash - 11/15/10 04:19 AM
so you did not have splice into the wires?
Posted By: cornet684me
Re: Dim and Bright lights in the dash - 11/15/10 04:21 AM
randy, is this a pic of the 40a rely?
Posted By: cornet684me
Re: Dim and Bright lights in the dash - 11/15/10 04:23 AM
thanks Randy, you read my mind , a visual is worth a thousand words, i think i can tackle it now with a diagram
Posted By: 1_WILD_RT
Re: Dim and Bright lights in the dash - 11/15/10 04:27 AM
Quote:
randy, is this a pic of the 40a rely?
Randy, I accidentally linked the wrong photo... The relays you want can be had at any car stereo/alarm store.. Get the relay harness too... 
Posted By: cornet684me
Re: Dim and Bright lights in the dash - 11/15/10 04:32 AM
Posted By: hooziewhatsit
Re: Dim and Bright lights in the dash - 11/15/10 04:35 AM
Quote:
so you did not have splice into the wires?
Well, yes and no. My relays came with a plug with 12" of wire coming off them. Instead of splicing that in, I used a tiny screwdriver to pop those connectors out, then cut into the harness, crimped the Napa spade connector on, and slid it into the plug. So the wires from the harness go directly into the plug to the relay.
Posted By: cornet684me
Re: Dim and Bright lights in the dash - 11/15/10 04:38 AM
hopefully i can do this too,
thanks
Posted By: BDW
Re: Dim and Bright lights in the dash - 11/15/10 11:38 AM
Another good idea, I put mine under the battery tray. Can't even tell with the battery installed.
Posted By: convx4
Re: Dim and Bright lights in the dash - 11/15/10 02:54 PM
I tucked my solid state voltage regulator, headlight relays and a accessory fuse panel under my battery. There is also room for the ECU, but I have converted to HEI on my 65 b-body.
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Posted By: convx4
Re: Dim and Bright lights in the dash - 11/15/10 02:56 PM
One with the ECU.
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Posted By: Yancy Derringer
Re: Dim and Bright lights in the dash - 11/15/10 07:55 PM
Sorry guys, I just cannot agree with "putting stuff under the battery."
That area ON A DRIVER is subject to a lot of road splash and grime, and on something that really does get driven, gets a certain amount of possible acid damage.
Also, having something like ignition under there makes things VERY difficult to troubleshoot
I do realize, you are trying to keep things clean looking, but for me, it's far more important that things work.
Posted By: cornet684me
Re: Dim and Bright lights in the dash - 11/16/10 01:48 AM
that is cool the way you did that
Posted By: convx4
Re: Dim and Bright lights in the dash - 11/16/10 03:29 AM
I made the accessory fuse panel store under the battery but flip out when needed.
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