I was able to track down the rare 2in pod tachometer and just got it in the mail today.I could not find any type of installation writeup on this anywhere. The back of the pod has a black wire and a grey wire and also a blue/red combo wire. Also there is a plug but no wire came on that plug.Any help would be appreciated!!

Ok my Tachometer did not come with a harness and I know what wire is what.

Tach has a black wire probably is a ground....so do i hook this wire to the black wire from the big clock? also I have a blue/red wire connected to the + positive location..do I piggy back this wire to the red wire from the big clock? I also have a grey wire...do I piggy back this wire off of the brown wire for illumination? just a bit of help here because I have no harness and can't seem to figure this out:(

Howdy,

"Also there is a plug but no wire came on that plug."

You have to identify this "plug". Is the light bulb installed? Is this possibly the socket where the bulb lives? If you have a bulb installed the wires coming from it should be obvious. My guess is the bulb is missing.

If you do have a bulb installed, one side of the bulb is connected to ground. The other side of the bulb needs to be switched through the light dimmer with the rest of the gauges. In the harness, that rheostat wire color is brown on all 240s AFAIK. If I am wrong someone will correct me. On the tachometer, that brown wire from the harness will be connected to the bulb.

I would not connect anything to the clock. Connect this tach just as you would an aftermarket tach; independent of the other gauges.

You can connect the black wire to any convenient ground.

Remember that you have to get the TACH signal from the coil (or ignition amp) to the tachometer. My guess, since I don't have my schematics with me, is that the blue/red wire is the signal wire to be connected to the TACH signal. DO NOT connect that wire to the red wire on the clock.

That leaves your gray wire. I don't want to flatly state that wire connects to key switched 12V because I don't have any documentation to prove it. But, if you do not have light bulb installed, that would be the only connection remaining.

--sd

Sd,

I thought the red and white wore in the cluster was the signal to the tachometer rather than the the blue and red wire...

I wish there was a write up on this tach since its a "Volvo" vdo gauge...

I thought the red and white wore in the cluster was the signal to the tachometer rather than the the blue and red wire...

Andi1, the red/white wire in the harness is the tach signal wire. (Back home now, got my prints here.) I thought the blue/red wire you mentioned is on the gauge side, as per your first post.

See my response to Art, which I will post immediately after this one.
--
Mr. Shannon DeWolfe -- I've taken to using mister because my name misleads folks on the WWW. I am a 53 year old fat man. ;-)

Good point, Andi.

Part of the problem must be the anachronism - putting an accessory tach into a 93, coming from an early 80's car. No issues, really, but I can't find any Volvo literature acknowledging its existence, and the 240's with dash space for 2" gauges (81-93) all had the large tach available where your clock is.

That's why it is rare?

Anyhow, before 85, the signal from the coil was gray (sheath color of the coaxial cable), not always white/red, so that may explain any gray wires you have that came with the tach.

Blue/red should go over to fuse 12 like I mentioned in my other reply to you.
--
Art Benstein near Baltimore

A banker is someone who lends you an umbrella when the sun is shining, and who asks for it back when it start to rain.

so is the object to "piggy back connect" the tach wires to other wires such as the brown wire connected to the cluster is for illumination...so would I piggy back connect the grey wire on the tach thats connected to the light bulb to one of the brown wires thats connected to the cluster??

And as far as the red/white wire that is supposed to be loose behind the cluster....I could not find it but I do remember once seeing it and trying to connect it to something....so I went ahead and disconnected the one red/white wire with a see through plastic cover from one of the prongs that has another prong below thats empty behind the temp guage and attached that to the G location of the tach.

Now the black wire that seems to run from the light bulb to the "-" marked black wire....is this ground you think? and the wire thats marked"+" is the positive or power wire? do I "piggy back connect these wires somewhere or what?

I'm sorry I'm not getting this....I guess I should have brought this one to the shop...it's just the shop wanted $180 for the install and I thought this was a bit steep for my budget...

Yes, you're right. There's no plug'n'play to this install; you'll have to do some piggy back connections for sure.

Andi, if you plugged that white/red wire onto the double terminal you can see here with a vinyl ring on this '89 cluster board, I'm surprised your speedometer isn't smoked. That's the cruise takeoff. It also connects directly to the fuel computer. Definitely do not put the white/red wire on the back of a cluster unless it is to a tach's G terminal.

If the light bulb has a gray wire, then that matches the pre-81 wiring color for dimmed gauge lighting. Piggy-back that into the brown wires running other light bulbs.

Black is usually ground, so if you've got it marked "-", then you've verified that. It might connect to the metal case of the tach (if it is metal) and to the other wire of the light. You will have to hunt for a ground: likely spot will be one of the lights the brown wires feed. They'll need a ground too, and I believe they will also be black.



Did you figure out your "alarm" yet?




--
Art Benstein near Baltimore

Be thankful for problems. If they were less difficult, someone with less ability might have your job.

Art,

Thanks so much for looking up some info and trying to help me out on this problem. I finally got the tach to work and got everything squared away!

For anyone that wants to do this its pretty easy the way I did it...

1.)
Connect power which is the blue/red wire on the tach to the fuse number one...really easy to install just attach a female plug to the wire and it slips right on to the back of the fuse.

2.)
Connect ground from the black wire marked as "-" (negative) on the tach and connect it to a circular terminal end and use a 5/8 nut and bolt and attach it to the ground plate in the back of this cluster hole.*(there are about 4 holes for you to decide where you want to install your wire.I used the farthest one top right)

3.)
Now its up to you whether you want to piggy back your illumination wire onto a brown cluster wire or do what I did and run another wire with a female plug end to fuse number 16 just like in step one.make sure you connect the wire thats on top of the bulb and on my tach its the Grey one since the black one is already your ground,

4.)
Now attach your red/white wire to the "G" prong located on the tach. It should be a loose red/white wire that has a female end and its shielded with see through plastic.

5.)
Now install the rubber grommets with the teeth facing the dash and pop in your tachometer! If everything works...go ahead and put your cluster and trim pieces back together and take a drive;)

----Andi 1----

Nice accomplishment.

I think in Step 3, your connecting the light to the full strength juice at fuse 16 is a better idea, especially if your 2" gauge lighting is as dim as the 2" clock.

Sunday well spent!
--
Art Benstein near Baltimore

Don't find fault, find a remedy. (Henry Ford)

If I am wrong someone will correct me.

You can always rely on that Shannon, right?


My guess, since I don't have my schematics with me, is that the blue/red wire is the signal wire to be connected to the TACH signal.

Way off. Blue/red is Volvo for ignition-switched battery. White/red has the tach signal, located behind the cluster (not connected), in 85-93 240s.

Some people call it the "Danger Will Robinson" wire, Mr. Shannon sir. That is because they find it while changing the Odo gear and think it has to be plugged on to something - then they plug it on the cruise tap or some spot and fry the speedometer. A little knowledge is dangerous, of course.

--
Art Benstein near Baltimore

Being right is highly overrated. Even a stopped clock is right twice a day.

Howdy Art,

You can always rely on that Shannon, right?

It is a good thing too. I need correction on a regular basis. ;-)

I am a bit confused though.

From the original post: The back of the pod has a black wire and a grey wire and also a blue/red combo wire. Also there is a plug but no wire came on that plug.

Since the blue/red is key switched 12V and the gray wire is to be connected to the wht/red in the harness, where is the brown wire for dimmed voltage? That is the reason I asked for verification on the presence of a bulb.

I've got my prints now so I am going to try to find the small tach in one of those if I can.

--
Mr. Shannon DeWolfe -- I've taken to using mister because my name misleads folks on the WWW. I am a 53 year old fat man. ;-)

Hi Mr. SDW,

... the gray wire is to be connected to the wht/red in the harness, ...

By now you've read the rest of the thread and know there's no suggestion to do that. Let us know if you find any Volvo info on the small tach. I looked and did not find.

Rare indeedy.




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Art Benstein near Baltimore

Don't let people drive you crazy when it is within walking distance.

Howdy all,

Art, I confused your mention of the gray sheathed coax wire with the gray wire reported to be on the tach.

No mention of the small tachometer in anything I've got.

Andi1, glad you figured it out despite me. ;-)

--
Mr. Shannon DeWolfe -- I've taken to using mister because my name misleads folks on the WWW. I am a 53 year old fat man. ;-)

When I ordered my '85 240 I ordered a tach, oil pressure, and volt gauges. The dealer (I think) installed then it was a cluster of 3 small gauges where the radio was placed on later 240s.

Look at Dave Barton's site - he has a diagram for this tach's connections. Also search here for messages regarding swapping the big clock for big tach - there you will find which wires you need to connect to get the rpm signal to the tach.

I'd be curious how your install goes as I also have a small tach and haven't had the chance or guts to install it.

I checked out dave barton site but I'm still a bit confused. I think I'm just going to wait till tomorrow and take everything apart and just picky back the power of some other power and ground connection and then attach the signal somewhere else. Do you think where the plug with the "G" is marked is ground or rpm??

Hi Andi,

The G on volvo gauges stands for "Gauge". The ground symbol will look like an upside-down T. You want to find the red/white wire, currently loose behind your instrument cluster, and plug that on the "G" terminal.

I think the illumination wires nearby for the center console are brown. Be careful not to short those to ground or your dimmer rheostat will smoke.

Power for the gauge should come from a fused ignition-switched circuit, like fuse #12.
--
Art Benstein near Baltimore

Drive carefully. It's not only cars that can be recalled by their maker.

I need some help on the 2in vdo tach also, does yours have the similiar pattern connectors as on the clock?