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I'm having a stab in the dark here.. cars that i have had with speed/tach have had two cables leading to engine and rear wheel for speed /front..try chasing the cables to the one that fits to the engine... un do it and see if wire inside cable is snapped...replace it should then work !!!
hope it helps

heads
 

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Hi,
It looks like you have two problems. Does your GL have the large tachometer and small (52 mm) clock? If so, does the clock work? If it does, you are getting power to the tachometer.
There should be a red and white wire connected to the back of tachometer to provide the signal and a three wire (black, green and red) harness that connects to the clock and provides it with power. Check that the red and white wire is connected correctly.
The odometer failure is probably a broken plastic gear which can be replaced.
 

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I know this is an archaic forum but I'm having a hell of a time getting my 52mm volvo tach to work. I've scoured the internet on this subject & everyone says you just need to hook up this red & white wire which is the tach signal...

I got back behind the dash & located the only red & white wire in sight which was in the cluster going into the instrument panel. I snipped that wire and hooked up it up to a multimeter and I'm getting no signal off of it. Everything works the same on the instrument panel so I don't think I snipped the wrong wire - does anyone have advice on this? I went off this diagram for hooking the tach up:

http://personal.linkline.com/dbarton/small...iagram/img0.gif

I've never had my door chime nor my dome light turn on/off with the door albeit I doubt this could relate to the tach.
 

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Make sure you have +12V between the + and - terminals.

On the earlier 240's (up til ~88), that white and red wire comes from the #1 coil connection. You should see AC volts (not necessarily DC) on that wire when the car is running.

If you have to, run a new wire from the coil to the gauge ...
 

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The 52 mm tachometer should have power (+ve) from a fuse that is turned off and on by the ignition switch -usually #13. In the original Volvo harness this is a blue/red wire. A black wire should be connected to ground (-ve) and the red/white wire should be connected to the signal terminal you'll also need power to the instrument light (tap off the instrument light circuit). This is a gray wire in some harness.
Don't confuse the yellow/red wire that goes to the bottom right of the cluster (relative to the front) with the red/white wire. The red/white wire should not be connected to a cluster with the big clock.
+ 1 on Robert240's comments, check that the other end of the red/white wire is still attached to the coil.
 

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Thank you for the responses - I checked & yeah I'm getting +12V between fuse #13 & the ground (and the lightbulb works fine coming off the gray wire). I recall the red/white was on the lower-left of the cluster, relative to the front - but i could be wrong, reaching behind the instrumental panel was a true ****. Anyway, over the weekend I'll have time to look behind there again.

Umm, kind of a dumb questions: this coil, what & where is it? I'm speculating it's gonna come down to running a wire directly from it per your suggestions.
 

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The coil is the balck cylinder mounted to the strut tower on the driver side - you'll have two terminals - one that says "1" (on the coil) and the other "15". What wires do you have on the #1 terminal?
 

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Alright - I had noticed this before but never pieced the problem together. The #1 side of the coil has just the plug with the white wire(s) coming off, the blue harness containing the red & white wires has never been connected, which I'm guessing is the problem. How is this supposed to connect though? Below is a picture.

 

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The blue connector is for diagnostic purposes only - The white wire is for adjusting the idle control motor and the pink is the AMM trim voltage - looks like you may need to run a new tach wire ....
 

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BTW: thank you so much - I now have this working swimmingly.

I was at my computer networking class & had some free time during a lab so I decided to go out to the parking lot & work on setting up the cable. I figured out how to do it, so I then took a CAT5 cable from the lab & hooked that up. It works perfectly & now looks like my car has ethernet running through it.
 
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