LS2 battery light hookup
Thread Starter
On The Tree
Joined: Jul 2006
Posts: 143
Likes: 0
From: great white northeast
LS2 battery light hookup Hi guys, Just finishing an LS2 Volvo 940 swap and one of the last items is getting the charge light in the Volvo dash to work. Since the LS2 alternator hookup is quite different from the LS1 setup I'm unsure of tying into the alternator harness for charge light operation. The plug on the LS2 alternator has 4 terminals but only the center 2 are utilized. The other 2 cannot be used since the plug is only formed for 2 connection. The ECM has a turn on signal and a duty cycle for proper voltage. The light in the dash (on a GM car) is turned on through serial data line that operates other guages also.
If I can't figure this out I might try building a simple board that will unground the Volvo dash (battery) light over a certain voltage. I was hoping for a simple solution. Wiring diagram enclosed.
Thanks for your input
If I can't figure this out I might try building a simple board that will unground the Volvo dash (battery) light over a certain voltage. I was hoping for a simple solution. Wiring diagram enclosed.
Thanks for your input
Does it provide the ground with the alternator running or when not?
I know nothing about volvos but id imagine if its your generic BATT light circuit then one side of the bulb receives IGN 12v and the other would receive 12V from the alt when running. If the alt is not running then the alt end is grounded hence the BATT light comes on.
One way to go about it is to ditch the PCM trigger and hook the charge light instead but I guess that would throw the MIL
Im also interested if there is a way to hook up a charge light and still retain the PCM trigger
I know nothing about volvos but id imagine if its your generic BATT light circuit then one side of the bulb receives IGN 12v and the other would receive 12V from the alt when running. If the alt is not running then the alt end is grounded hence the BATT light comes on.
One way to go about it is to ditch the PCM trigger and hook the charge light instead but I guess that would throw the MIL
Im also interested if there is a way to hook up a charge light and still retain the PCM trigger
Thread Starter
On The Tree
Joined: Jul 2006
Posts: 143
Likes: 0
From: great white northeast
Yes a generic light bulb circuit just like any old Chevy up to 04. I'm using EFIlive so I can ditch the code. I might be a bit **** so I'd rather not. Would love to have the light work correctly and don't mind spending some money to do so...whatever it takes. This is a really nice swap. Homegrown stainless long tubes an full stainless exhaust, aluminum everything else. I'm a geezer...I'll drive this thing till I die; really. Have mucho time and money invested in it, and wan't it right.
I'm thinking of making some kind of voltage operated switch that will trip a relay at say 12.8 volts so I know it's charging. I thought there might be an easier way. I Checked Street & Performance tech stuff but no luck. This should be a no brainer for any LS2 swap. Looks like I'm the first guy with an E-40 ecm who wants his battery light to work in a non-gm car....go figure.
I'm thinking of making some kind of voltage operated switch that will trip a relay at say 12.8 volts so I know it's charging. I thought there might be an easier way. I Checked Street & Performance tech stuff but no luck. This should be a no brainer for any LS2 swap. Looks like I'm the first guy with an E-40 ecm who wants his battery light to work in a non-gm car....go figure.
Staging Lane
Joined: Nov 2006
Posts: 74
Likes: 3
From: Southwest Missouri
And I'm the second guy who's trying to figure out the same issue. I just fired my Gen IV 5.3 in my 1987 535iS BMW for the first time yesterday--well, first time in the car. I'm going to run an accessory volt meter but I was thinking it would be nice to keep the BMW warning light also. I was tracing wiring diagrams over the weekend and hadn't figured anything out. Let's hope some smart guy brings us an answer.
The Geezer
The Geezer
Thread Starter
On The Tree
Joined: Jul 2006
Posts: 143
Likes: 0
From: great white northeast
GEEEEZ Geezer. Where ya been hiding? followed your whole series on youtube but it's like you vanished.
Anywho I think I found an answer. I found this relay on the net. Haven't bought it yet. It's adjustable check it out. It can be wired to ground the bulb in your BMW dash at a certain voltage. You can leave the alternator right out of the equation with this gadget. http://www.kussmaul.com/091-96-12.html
Geezer, I have the same engine in this old Volvo. Hoping for 30 MPG. Hope I'm not blowing smoke!
Anywho I think I found an answer. I found this relay on the net. Haven't bought it yet. It's adjustable check it out. It can be wired to ground the bulb in your BMW dash at a certain voltage. You can leave the alternator right out of the equation with this gadget. http://www.kussmaul.com/091-96-12.html
Geezer, I have the same engine in this old Volvo. Hoping for 30 MPG. Hope I'm not blowing smoke!
Trending Topics
Thread Starter
On The Tree
Joined: Jul 2006
Posts: 143
Likes: 0
From: great white northeast
Anywho,
For those of you wondering about the LS2 battery light in a conversion. That relay link I posted in last post turned out to do the trick. Now my battery light works just fine. Easy to wire up (under the dash) and great directions. The bad thing is the cost (about $60 bucks).
Oh and on European cars of the early 90s with an airbag. That battery light also tells the airbag ECU that the engine is running. This is important!
For those of you wondering about the LS2 battery light in a conversion. That relay link I posted in last post turned out to do the trick. Now my battery light works just fine. Easy to wire up (under the dash) and great directions. The bad thing is the cost (about $60 bucks).
Oh and on European cars of the early 90s with an airbag. That battery light also tells the airbag ECU that the engine is running. This is important!
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?
Pouria Savadkouei
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo Thread Starter
On The Tree
Joined: Jul 2006
Posts: 143
Likes: 0
From: great white northeast
The primary side of the relay just needs to sense voltage to be able to switch on or off at an adjustable voltage setting. I just hooked that part through the ignition switch. You can download the directions and see how the relay works. You can use it either normally open or normally closed to suite your liking. It comes preset at 11.8 volts. I bumped it up to 12.6 since that is the voltage of a fully charged battery.
Works great, John
Works great, John
