Classic Mustangs List Archive

This read-only message was archived from a public mail list.
Mail From: keven (Coates, Keven)

Chris, you beat me to it! That's just what I was going to say.

Keven

-----Original Message-----
From: classic-mustangs-bounces at lists.twistedpair.ca [mailto:classic-mustangs-bounces at lists.twistedpair.ca] On Behalf Of Chris Kelly
Sent: Monday, March 22, 2010 10:43 PM
To: Coates, Keven
Subject: Re: [CM] A circuit that is broken when the ignition is in the ON or ACC positions

Place a relay in the power to the trunk latch solenoid, wired so that the NC
(normally closed) contacts complete the circuit to the trunk release. Run a
power feed (fused - about 5A) from a connection that is hot in both ON and
ACC to the relay coil power that will then open the relay with the ignition
on or in ACC. With the relay "on" the truck release circuit would be "open"
and the release buttons would not work.

This read-only message was archived from a public mail list.
Mail From: ckelly (raceabilene)

I "cheated". I just had to do a similar setup on the mustang. Built
a dual relay setup to enable a single switch to power up the fans and
water pump drive for cooling with the ignition off. With ignition on,
the water pump has to be on and the fans on thermostat trigger. The
wimpy fans need about 2 minutes to coll the car after a run. A little
relay logic and it's all done.

On Mar 23, 2010, at 8:14 AM, "Coates, Keven" <keven at ti.com> wrote:

> Chris, you beat me to it! That's just what I was going to say.
>
> Keven
>
> -----Original Message-----
> From: classic-mustangs-bounces at lists.twistedpair.ca [mailto:classic-
> mustangs-bounces at lists.twistedpair.ca] On Behalf Of Chris Kelly
> Sent: Monday, March 22, 2010 10:43 PM
> To: Coates, Keven
> Subject: Re: [CM] A circuit that is broken when the ignition is in
> the ON or ACC positions
>
> Place a relay in the power to the trunk latch solenoid, wired so
> that the NC
> (normally closed) contacts complete the circuit to the trunk
> release. Run a
> power feed (fused - about 5A) from a connection that is hot in both
> ON and
> ACC to the relay coil power that will then open the relay with the
> ignition
> on or in ACC. With the relay "on" the truck release circuit would
> be "open"
> and the release buttons would not work.
> _______________________________________________
> Classic-mustangs mailing list
> Classic-mustangs at lists.twistedpair.ca
> lists.twistedpair.ca/mailman/listinfo.cgi/classic-mustangs
>
> Visit the Classic Mustang Wiki! sauce.donair.org/~cm/

This read-only message was archived from a public mail list.
Mail From: W427 (David)

Hey Chris - you know you can go one step further and use a 'delay relay'
from the boneyard to get your 2-minute run with auto-shutoff so you
don't have to remember. Set it and forget it... lol. Here is a basic
schematic to build your own mod on a standard relay as well, if you
like. <i40.tinypic.com/14n3itd.jpg> I can grab one I've done
for the parts numbers and values. Many parts will work, though.

David

raceabilene wrote:
> I "cheated". I just had to do a similar setup on the mustang. Built
> a dual relay setup to enable a single switch to power up the fans and
> water pump drive for cooling with the ignition off. With ignition on,
> the water pump has to be on and the fans on thermostat trigger. The
> wimpy fans need about 2 minutes to coll the car after a run. A little
> relay logic and it's all done.
>
> On Mar 23, 2010, at 8:14 AM, "Coates, Keven" <keven at ti.com> wrote:
>
>
>> Chris, you beat me to it! That's just what I was going to say.
>>
>> Keven
>>
>> -----Original Message-----
>> From: classic-mustangs-bounces at lists.twistedpair.ca [mailto:classic-
>> mustangs-bounces at lists.twistedpair.ca] On Behalf Of Chris Kelly
>> Sent: Monday, March 22, 2010 10:43 PM
>> To: Coates, Keven
>> Subject: Re: [CM] A circuit that is broken when the ignition is in
>> the ON or ACC positions
>>
>> Place a relay in the power to the trunk latch solenoid, wired so
>> that the NC
>> (normally closed) contacts complete the circuit to the trunk
>> release. Run a
>> power feed (fused - about 5A) from a connection that is hot in both
>> ON and
>> ACC to the relay coil power that will then open the relay with the
>> ignition
>> on or in ACC. With the relay "on" the truck release circuit would
>> be "open"
>> and the release buttons would not work.

This read-only message was archived from a public mail list.
Mail From: ckelly (Chris Kelly)

That's an idea - what's a good source for the relays?

=====================================
Chris Kelly - ckelly at raceabilene.com
raceabilene.net/kelly/hotrod
Merkel, Texas
Member:
International Hot Rod Association
Abilene Performance Car Association
Falcon Club of America
=====================================

> -----Original Message-----
> From: classic-mustangs-bounces at lists.twistedpair.ca [mailto:classic-
> mustangs-bounces at lists.twistedpair.ca] On Behalf Of David
> Sent: Tuesday, March 23, 2010 5:43 PM
> To: Chris Kelly
> Subject: Re: [CM] A circuit that is broken when the ignition is in the ON
> or ACC positions
>
> Hey Chris - you know you can go one step further and use a 'delay relay'
> from the boneyard to get your 2-minute run with auto-shutoff so you
> don't have to remember. Set it and forget it... lol. Here is a basic
> schematic to build your own mod on a standard relay as well, if you
> like. <i40.tinypic.com/14n3itd.jpg> I can grab one I've done
> for the parts numbers and values. Many parts will work, though.
>
> David
>

This read-only message was archived from a public mail list.
Mail From: W427 (David)

Lots of sources, like time-delay headlights, interior lights, power
window delays, cooling fan after-run delays, seatbelt warning light
relays, etc. For example, I found a low power one in a 1990 Saab 9000
behind the glove box for the interior lights, and another high-amp one
under the hood for cooling fan after-run. It even said TIME RELAY on
it. A slick one I used once was the auto on/off headlight relay from an
'88 Cadillac, which had variable time delay with a sliding switch
(potentiometer) so the delay was whatever I wanted, about 5 seconds up
to something like 4 minutes. Anyway, there are lots of options, but if
I need one these days, I just assemble my own for the purpose.

Speaking of, I recall a 2-minute relay timer I built for a buddy that
used the schematic I posted, and the parts were:

Resistor: 1.5M
Capacitor: 47uF
MOSFET: 2N7000

I might be off on a value, but that's right or close to it. All the
parts cost about a quarter combined (although I had to meet a $5 minimum
order + shipping) and can fit inside a standard relay housing with
careful positioning and soldering.

David

Chris Kelly wrote:
> That's an idea - what's a good source for the relays?
>
>
>> -----Original Message-----
>>
>> Hey Chris - you know you can go one step further and use a 'delay relay'
>> from the boneyard to get your 2-minute run with auto-shutoff so you
>> don't have to remember. Set it and forget it... lol. Here is a basic
>> schematic to build your own mod on a standard relay as well, if you
>> like. <i40.tinypic.com/14n3itd.jpg> I can grab one I've done
>> for the parts numbers and values. Many parts will work, though.
>>
>> David

This read-only message was archived from a public mail list.
Mail From: ckelly (raceabilene)

Cool - very good info there, thank you. I'm sure I can find a few
things at digikey to meet any min purchase deal. It'll be a while
before I get a sabbatical to the wrecking yard so I'll need to file
this away.

On Mar 23, 2010, at 10:38 PM, David <W427 at comcast.net> wrote:

> Lots of sources, like time-delay headlights, interior lights, power
> window delays, cooling fan after-run delays, seatbelt warning light
> relays, etc. For example, I found a low power one in a 1990 Saab 9000
> behind the glove box for the interior lights, and another high-amp one
> under the hood for cooling fan after-run. It even said TIME RELAY on
> it. A slick one I used once was the auto on/off headlight relay
> from an
> '88 Cadillac, which had variable time delay with a sliding switch
> (potentiometer) so the delay was whatever I wanted, about 5 seconds up
> to something like 4 minutes. Anyway, there are lots of options, but
> if
> I need one these days, I just assemble my own for the purpose.
>
> Speaking of, I recall a 2-minute relay timer I built for a buddy that
> used the schematic I posted, and the parts were:
>
> Resistor: 1.5M
> Capacitor: 47uF
> MOSFET: 2N7000
>
> I might be off on a value, but that's right or close to it. All the
> parts cost about a quarter combined (although I had to meet a $5
> minimum
> order + shipping) and can fit inside a standard relay housing with
> careful positioning and soldering.
>
> David
>
> Chris Kelly wrote:
>> That's an idea - what's a good source for the relays?
>>
>>
>>> -----Original Message-----
>>>
>>> Hey Chris - you know you can go one step further and use a 'delay
>>> relay'
>>> from the boneyard to get your 2-minute run with auto-shutoff so you
>>> don't have to remember. Set it and forget it... lol. Here is a
>>> basic
>>> schematic to build your own mod on a standard relay as well, if you
>>> like. <i40.tinypic.com/14n3itd.jpg> I can grab one I've
>>> done
>>> for the parts numbers and values. Many parts will work, though.
>>>
>>> David
> _______________________________________________
> Classic-mustangs mailing list
> Classic-mustangs at lists.twistedpair.ca
> lists.twistedpair.ca/mailman/listinfo.cgi/classic-mustangs
>
> Visit the Classic Mustang Wiki! sauce.donair.org/~cm/

This read-only message was archived from a public mail list.
Mail From: keven (Coates, Keven)

>Speaking of, I recall a 2-minute relay timer I built for a buddy that
used the schematic I posted, and the parts were:

If you guys want to build this, that's great. It's an exercise that's fun useful, and educational.

If you want it to last, it will need a few tweaks for it to last in the harsh electrical environment that is automotive. I can look at it and give you some recommendations. Most likely it would only be a few additional parts.

As it is, it could last a while, but given the voltage spikes normally found in most automotive systems, most likely it would fail eventually. MOSFETs are very sensitive to voltage spikes, which is the reason mechanical relays are still used by OEMs except in circuitry that has additional protection built in. When it would fail depends on the car and what's on the electrical system. On some cars it may only work once. Some cars it may last years.

We have an automotive group here at Texas Instruments (where I work) and I've been gleaning knowledge from them for a while. It's amazing the standards OEM circuitry has to go through for reliability. I built some LED tail lights for my Mustang many years ago, and they're still working great, so I have some experience here.

Keven

This read-only message was archived from a public mail list.
Mail From: W427 (David)

An HTML attachment was scrubbed...
URL: lists.twistedpair.ca/pipermail/classic-mustangs/attachments/20100324/cf91229a/attachment.html

This read-only message was archived from a public mail list.
Mail From: keven (Coates, Keven)

>Indeed, I was amiss to state I always add diodes (generally 1N4001 cheapos) to any induction circuit such as this relay coil to protect ECUs, radios, and such. While most relays come with a small resistor shunt between the coil feeds (terminals 85 & 86 per Bosch), I generally snip those out and place a 'reversed' diode to suppress any spikes. The spikes generated by these little coils is impressive.

Yes it is, and that's another thing I'd add. The 20V Zener is on the input and a regular diode on the output to the coils for back emf. The voltage spikes that all OEM electronics have to handle without blowing are severe. The standard is something like a 50V reverse spike and a 90V forward spike (for only a few ms of course). The Zener will protect against both of those situations.

>I have used the coil from one of the tiny Ford relays and a transistor to make a voltage spike from a 5v ECU signal to feed an aftermarket tachometer that is normally fed a direct ignition coil signal (voltage trigger). Worked like a charm. It's the equivalent of the MSD "Tach Adapter" at 1% the price.

That's a good idea!

>Perhaps it's the particular MOSFET I'm using, but of the several time delay relays I've made for various purposes, they're all still working fine at last count.

That particular mosfet is very high voltage (for a MOSFET) at 60V. That gives it a pretty good amount of margin. I'd still add the Zener though. It's only one part and cheap. I'll post the schematic with Chris.

Good info!
Keven
-------------- next part --------------
An HTML attachment was scrubbed...
URL: lists.twistedpair.ca/pipermail/classic-mustangs/attachments/20100325/4468209f/attachment.html

This read-only message was archived from a public mail list.
Mail From: Andre.Pollard (Andre.Pollard


There are lots (most?) of MOSFETs designed for inductive use. They include
the protection in the package. The ones I've gotten for autmotive use also
included protection for gate surges.

Static, however, will kill them quick, It's important to prevent static
discharge until they are in a grounded circuit to prevent a dead MOSFET.



David
<W427 at comcast.net>
Sent by: To
classic-mustangs-bounce Andre
s at lists.twistedpair.ca <Andre.Pollard at clariant.com>
cc

Subject
Re: [CM] A circuit that is
03/24/2010 11:08 PM broken when the ignition is
in the ON or ACC
positions








Please respond to
A list for owners of
Classic Mustangs
<classic-mustangs at lists
.twistedpair.ca>






Indeed, I was amiss to state I always add diodes (generally 1N4001 cheapos)
to any induction circuit such as this relay coil to protect ECUs, radios,
and such. While most relays come with a small resistor shunt between the
coil feeds (terminals 85 & 86 per Bosch), I generally snip those out and
place a 'reversed' diode to suppress any spikes. The spikes generated by
these little coils is impressive. I have used the coil from one of the
tiny Ford relays and a transistor to make a voltage spike from a 5v ECU
signal to feed an aftermarket tachometer that is normally fed a direct
ignition coil signal (voltage trigger). Worked like a charm. It's the
equivalent of the MSD "Tach Adapter" at 1% the price.

Perhaps it's the particular MOSFET I'm using, but of the several time delay
relays I've made for various purposes, they're all still working fine at
last count.

David

Coates, Keven wrote:
Speaking of, I recall a 2-minute relay timer I built for a
buddy that

used the schematic I posted, and the parts were:

If you guys want to build this, that's great. It's an exercise
that's fun useful, and educational.

If you want it to last, it will need a few tweaks for it to last in
the harsh electrical environment that is automotive. I can look at
it and give you some recommendations. Most likely it would only be a
few additional parts.

As it is, it could last a while, but given the voltage spikes
normally found in most automotive systems, most likely it would fail
eventually. MOSFETs are very sensitive to voltage spikes, which is
the reason mechanical relays are still used by OEMs except in
circuitry that has additional protection built in. When it would
fail depends on the car and what's on the electrical system. On some
cars it may only work once. Some cars it may last years.

We have an automotive group here at Texas Instruments (where I work)
and I've been gleaning knowledge from them for a while. It's amazing
the standards OEM circuitry has to go through for reliability. I
built some LED tail lights for my Mustang many years ago, and they're
still working great, so I have some experience here.

Keven
_______________________________________________
Classic-mustangs mailing list
Classic-mustangs at lists.twistedpair.ca
lists.twistedpair.ca/mailman/listinfo.cgi/classic-mustangs

Visit the Classic Mustang Wiki! sauce.donair.org/~cm/

_______________________________________________
Classic-mustangs mailing list
Classic-mustangs at lists.twistedpair.ca
lists.twistedpair.ca/mailman/listinfo.cgi/classic-mustangs

Visit the Classic Mustang Wiki! sauce.donair.org/~cm/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: lists.twistedpair.ca/pipermail/classic-mustangs/attachments/20100325/e1155d62/attachment-0001.html
-------------- next part --------------
A non-text attachment was scrubbed...
Name: pic03618.gif
Type: image/gif
Size: 1255 bytes
Desc: not available
Url : lists.twistedpair.ca/pipermail/classic-mustangs/attachments/20100325/e1155d62/attachment-0001.gif