1986 Chevrolet Celibity

Nate Nagel wrote:
> Scott Dorsey wrote:
>> Toyota MDT in MO > wrote:
>>> Scott Dorsey wrote:
>>>
>>>> In '86, the fan was probably controlled directly by a
>>>> temperature-control
>>>> switch, rather than by the engine computer.
>>> It is controlled by a coolant temp switch input to the fan relay
>>> (closed at 230*F); this circuit is also paralleled to a relay output
>>> that requires A/C clutch command (depends on engine option: V5 runs
>>> all the time and the DA6 cycles) and ECM approval before closing the
>>> fan relay.
>>
>> AAARGH! Why all this crap just for a simple fan? This is the kind of
>> stuff German car makers do.
>>
>> So... first step is to check the fan relay.....
>> ---scott
>
> No they don't, or at least didn't start doing it until much later.
> All my German cars (well, not sure about the '02 GTI) used a simple
> thermoswitch in the radiator, and a relay (also tied into the A/C if
> car has it.) That's it.
>
> People accuse German cars of being overly complex, and in some cases
> that is justified, but it's a really recent phenomenon.
> Overengineered, yes, but overly complex...
>
> Now I would say "that's the kind of thing I'd expect from a Japanese
> car" :P
>
> nate
>
Toyota didn't start using ECM fan control until about 2000ish; 2002
Camry, 2003 Corolla, and 2004 Sienna are a few specific examples.

:P right back at ya!

--
Toyota MDT in MO

Nate Nagel > wrote in
:


>
> People accuse German cars of being overly complex, and in some cases
> that is justified, but it's a really recent phenomenon.
> Overengineered, yes, but overly complex...
>
> Now I would say "that's the kind of thing I'd expect from a Japanese
> car" :P
>



Honda didn't even start using relays in their fan control until about 1992.

Prior to that it was a simple thermal switch to ground through the fan
motor; as crude as it can get.



--
Tegger

> Good advice. *I hope the well known mechanic referenced in the above
> riveting story heeds it. *Then he can move on to discover the most
> likely failed relay, thereby taking a logical diagnostic path towards a
> solution.
>

The guy might be well known, butif he cant diagnose a simple
circuit....
Power, ground and relay trigger is all...
But seriously, I diagnosed a ton of these by looking at the relay
connector... when these things fail they
tend to leave heat evidence at the relay connection.
HTH
Ben

ben91932 wrote:
>> Good advice. I hope the well known mechanic referenced in the above
>> riveting story heeds it. Then he can move on to discover the most
>> likely failed relay, thereby taking a logical diagnostic path towards a
>> solution.
>>
>>
>
> The guy might be well known, butif he cant diagnose a simple
> circuit....
> Power, ground and relay trigger is all...
> But seriously, I diagnosed a ton of these by looking at the relay
> connector... when these things fail they
> tend to leave heat evidence at the relay connection.
> HTH
> Ben
>

HTH? You're assuming the well known mechanic knows of this thread *and*
can read.

--
Toyota MDT in MO

On Jul 1, 9:10*pm, Tegger > wrote:
> Nate Nagel > wrote :
>
>
>
> > People accuse German cars of being overly complex, and in some cases
> > that is justified, but it's a really recent phenomenon.
> > Overengineered, yes, but overly complex...
>
> > Now I would say "that's the kind of thing I'd expect from a Japanese
> > car" :P
>
> Honda didn't even start using relays in their fan control until about 1992.
>
> Prior to that it was a simple thermal switch to ground through the fan
> motor; as crude as it can get.
>
> --
> Tegger

my civic doesn't even have a horn relay; i thought most cars adopted
them when air bags came in and the horn button became a tiny item with
tiny contacts rather than a big robust jobbie.
and it didn't have a headlight relay; it does now (on the advice of
daniel stern the lighting guy who posts here sometimes) along with
decently large gauge wire, and thats perked up the lighting with stock
wattage bulbs more than higher wattage bulbs did with the stock
wiring.

On Jul 6, 2:15*am, z > wrote:
> On Jul 1, 9:10*pm, Tegger > wrote:
>
>
>
>
>
> > Nate Nagel > wrote :
>
> > > People accuse German cars of being overly complex, and in some cases
> > > that is justified, but it's a really recent phenomenon.
> > > Overengineered, yes, but overly complex...
>
> > > Now I would say "that's the kind of thing I'd expect from a Japanese
> > > car" :P
>
> > Honda didn't even start using relays in their fan control until about 1992.
>
> > Prior to that it was a simple thermal switch to ground through the fan
> > motor; as crude as it can get.
>
> > --
> > Tegger
>
> my civic doesn't even have a horn relay; i thought most cars adopted
> them when air bags came in and the horn button became a tiny item with
> tiny contacts rather than a big robust jobbie.
> and it didn't have a headlight relay; it does now (on the advice of
> daniel stern the lighting guy who *posts here sometimes) along with
> decently large gauge wire, and thats perked up the lighting with stock
> wattage bulbs more than higher wattage bulbs did with the stock
> wiring.

Heck, I thought *all* cars had horn relays! My '55 Stude has one, and
I'm sure that it wasn't new for that year.

The nice thing about using a horn relay is then you don't have all
that juice traveling up the steering column, which used to be metal
back in the day (although you still have the directional signal
wires...) the horn wire in the column is current-limited by the horn
relay coil.

nate

Tegger wrote:
> Nate Nagel > wrote in
> :
>
>
>
>> People accuse German cars of being overly complex, and in some cases
>> that is justified, but it's a really recent phenomenon.
>> Overengineered, yes, but overly complex...
>>
>> Now I would say "that's the kind of thing I'd expect from a Japanese
>> car" :P
>>
>>
>
>
>
> Honda didn't even start using relays in their fan control until about 1992.
>
> Prior to that it was a simple thermal switch to ground through the fan
> motor; as crude as it can get.
>
>
>
>

Do you know of a (for example) late 80's Honda that works as you say?
I'm not aware of one.

--
Toyota MDT in MO

Toyota MDT in MO > wrote in
:

> Tegger wrote:
>> Nate Nagel > wrote in
>> :
>>
>>
>>
>>> People accuse German cars of being overly complex, and in some cases
>>> that is justified, but it's a really recent phenomenon.
>>> Overengineered, yes, but overly complex...
>>>
>>> Now I would say "that's the kind of thing I'd expect from a Japanese
>>> car" :P
>>>
>>>
>>
>>
>>
>> Honda didn't even start using relays in their fan control until about
>> 1992.
>>
>> Prior to that it was a simple thermal switch to ground through the
>> fan motor; as crude as it can get.
>>
>>
>>
>>
>
> Do you know of a (for example) late 80's Honda that works as you say?
> I'm not aware of one.
>



I might have been a bit too broad with my original comment.

On further investigation it looks like the no-relay arrangement was the
case only with rad fans on vehicles _without_ A/C. Cars _with_ A/C always
had relays to carry rad fan current.

I find numerous non-A/C Hondas from the late '80s up to 1991 with no relays
for the rad fan. My 1991 Integra is one of them. The rad fan thermo-
switches on those cars are not too reliable.


--
Tegger

z > wrote in
:

> On Jul 1, 9:10*pm, Tegger <invalid @ invalid.inv> wrote:
>> Nate Nagel <njnagel @ roosters.net> wrote
>>
> om:
>>
>>
>>
>> > People accuse German cars of being overly complex, and in some
>> > cases that is justified, but it's a really recent phenomenon.
>> > Overengineered, yes, but overly complex...
>>
>> > Now I would say "that's the kind of thing I'd expect from a
>> > Japanese car" :P
>>
>> Honda didn't even start using relays in their fan control until about
>> 1992.
>>
>> Prior to that it was a simple thermal switch to ground through the
>> fan motor; as crude as it can get.
>>
>> --
>> Tegger
>
> my civic doesn't even have a horn relay; i thought most cars adopted
> them when air bags came in and the horn button became a tiny item with
> tiny contacts rather than a big robust jobbie.




If you have SRS, you have a horn relay. As far as I'm aware, only non-SRS
Hondas had no horn relay. (I'm trying to be careful here so as to prevent
that Toyota guy from Missouri calling me on this.)

On those non-SRS cars, I've seen surface corrosion on the little brass tab
that carries current from the wiring to the slip ring prevent the horn from
working fully (horn makes a sort of buzzing noise instead). Sand the tab
nice and clean and things are OK again. Tends to get diagnosed as bad
horns.


--
Tegger

Tegger wrote:
> Toyota MDT in MO > wrote in
> :
>
>
>> Tegger wrote:
>>
>>> Nate Nagel > wrote in
>>> :
>>>
>>>
>>>
>>>
>>>> People accuse German cars of being overly complex, and in some cases
>>>> that is justified, but it's a really recent phenomenon.
>>>> Overengineered, yes, but overly complex...
>>>>
>>>> Now I would say "that's the kind of thing I'd expect from a Japanese
>>>> car" :P
>>>>
>>>>
>>>>
>>>
>>> Honda didn't even start using relays in their fan control until about
>>> 1992.
>>>
>>> Prior to that it was a simple thermal switch to ground through the
>>> fan motor; as crude as it can get.
>>>
>>>
>>>
>>>
>>>
>> Do you know of a (for example) late 80's Honda that works as you say?
>> I'm not aware of one.
>>
>>
>
>
>
> I might have been a bit too broad with my original comment.
>
> On further investigation it looks like the no-relay arrangement was the
> case only with rad fans on vehicles _without_ A/C. Cars _with_ A/C always
> had relays to carry rad fan current.
>
> I find numerous non-A/C Hondas from the late '80s up to 1991 with no relays
> for the rad fan. My 1991 Integra is one of them. The rad fan thermo-
> switches on those cars are not too reliable.
>
>
>

I'll be damned! I can't remember the last Honda product I saw without
A/C. I checked many diagrams from the 80's before asking the question,
and they all show (perhaps erroneously) two relays and two fans being
employed with or without A/C. I then checked your car specifically and
the diagram is correct as you describe it. What a piece of crap setup!
Have you considered (or already tried) wiring in a relay? I've done
that with success on the older Toyota neutral safety circuits that get
gummed up inside the PRNDL switch housing and can't handle starter
solenoid current anymore. Another quality omission of a $0.50 relay.

I just checked the only paper OEM EWD I still have (1990 Civic, all
models) and it shows one fan, one relay on the without A/C system. The
88 Civic rollout is about as far back as I can remember anyway :-)

--
Toyota MDT in MO