Anyone work on the gauges in the instrument cluster?? I have 2 gauges that are not working correctly. I would rather fix them than put new gauges on the dash.

The Temperature and Oil pressure gauges are not working properly. Doing a search on here, I found a couple people going to give it a try, but no further postings. BTW the sending units on each have been replaced a couple times. I am rather electrically inclined and going to give it a try. First thing is to verify the sending units working.

A few people mentioned cracks in the plastic traces on the back of the cluster. Anyone have any luck??

Has anyone taken out the sections of the gauges??? It looks like the oil pressure and fuel level are on one section and the temp and voltage are on another.

My truck is a 1988 XLT so it does have the tach. I have an old 88 without a tach and the gauges are different. From what I can tell the cluster fits 87-91 Bronco and F series.

I will try to have a look when I get a chance and report back.

 

Yes the 87 to 91 clusters are the same and its plug and play for tach and non tach clusters.

As you have a 88 tach cluster, just install it in to your 88 truck, its plug and play. That way you can find out if the original cluster has the issue or its a wiring problem if the "new" cluster acts up as the old one does.

What are the gauges doing? One test is to short out the sending wire to the engine and see if the gauge pegs to full scale and returns back to low scale when the short is removed. If they work ok that way then problem most likely not a cluster issue.

Check the engine ground to cab ground, that is usually a problem on older trucks.

 

The one I have in my truck has a tach, the spare one I have does not. I just check with a junk yard and they said $25 if they have one and I pull it. Sounds good. Not that hard of a deal.

What are the gauges doing??? Well the oil gauge sits on no oil pressure and make the Engine light come on. If I short the wire out on the engine the gauge jumps to the right. If I hook it back up it used to work for a while. I think it is sticking at the bottom of the scale.

The temp gauge sits at 1/3rd scale when it is cold, When it is warm it goes to 2/3rds scale. I think it may be sticking too. I put a new sending unit on it and does the same thing. Next step was to put a test meter on the senders and see what they ohm out at and if they change properly when oil pressure and temp changes.

Right now I have some engine problems to work out.

 

He was saying to put the non tach cluster in the truck with the tach cluster and see if the gauges work. If they do then it is a gauge issue so the wiring and sensor is good.

 

Ok, I wasn't clear on if the non tach and tach clusters were interchangeable. Mine look quite different. (probably because of the tach) I seen a guy years ago, on a car, smoke some wires putting a tach in a tachless car by doing a swap. Wanted to get clarification. Thanks

 

He answered this question in his first sentence.

 

Like I said clarification. I wasn't sure if he meant all the tach models are the same, and all the non tach are the same, or the tach and non tach can be interchanges.

When you see the fine traces on the back of a cluster, one wrong wire can melt them. Making more of a problem.

 

I forgot about the 87 cluster(both tach and non tach), the oil gauge was a "real" gauge, which means it will show the engine's actual oil pressure.

Starting in 88 Ford decided to make oil gauge in into a fancy idiot light gauge. That means the sending unit will close when the oil pressure is above 8psi. The cluster has been modified to show this a middle range on the gauge. You may have a compatiblity issue with the cluster and sending unit.

As the cluster shows the check gauges light when the oil pressure gauge is low, I think it is working properly and you may have wrong oil sending unit or wire issue from cluster to sending unit.

If you do have 88 to 91 cluster and want to get the "real" oil gauge working, its a simple thing to do, just find that 20ohm resistor on the cluster's foil pcb and jumper it with a wire(short it out) and replace the oil sending unit with a 86 and older oil sending unit(its the big one). There are a few threads on here with photos I recall.

As the temp gauge also show kinda the same problem, I suspect a bad ground from engine to chassis and cab. That bad ground drove me nuts on my 89 F250. I fixed it by running new grounding cable from battery to engine and cab directly.

 

From what I can tell the real gauge was converted to the idiot gauge on different years depending on models. Somewhere about 86 through 90.

I am going to pull the dash and verify whether it has the resister or not. Also I will check the resistances of the sending units at the back of the gauges.

As far as a ground issue, it may be a possibility, but I just put the engine in, and I know 4 of the grounds are in good shape. Body to engine, engine to battery, engine to frame, and wiring harness ground.

Thanks to all for the info. Will continue with this after I get my oil problem knocked out. Busy weekend and the oil pump is bad on the rebuilt engine. Urgh...

 

I can't find any threads with the part numbers. Would you know what they are are?? I think it is a PS 4 (az) or bwd s334 (adv)

I think the gauge is working properly for the oil pressure, not the sender.

Lets start with this. When you short the sender wire out to ground. The gauge pegs to the right. When the wire is open it goes to the left. So that means high resistance left, low resistance right OK.... Mine does that.

On the Wells website the ps60 sending unit is supposed to be open under 4 psi.. Correct... then the resistance should got from 24 ohms low pressure to 10 ohms high pressure. Ok that sound right.

Well I just picked up a new PS 60 and at 100psi I am getting 180 ohms, and at 50 psi I am getting 160 ohms. That sounds the opposite. Either I have the wrong part number (which means the wells site has bad info) or the sender is bad out of the box.

Not sure how good you are at electronics, Maybe you could tell me what you think... Thx

 

That is correct, to the left is high resistance and to the right is low resistance. As your oil gauge is going fully into the high range when you short the sending wire, it means you have a fully working oil gauge. If it did not, then the oil gauge would only go mid scale when shorted and would be the "idiot light" oil gauge.

The sending unit you will need will come off a 85/86 F1x0 as they have the real guage. The sending unit is 3 times bigger than the "idiot" sending unit. So you might have to extened the sending unit's mount depending on which engine you have.






Here's some reading about this... https://www.ford-trucks.com/forums/1...e-cluster.html

I have over 25 years now in electronics repair and still run across head pounding problems. LOL

 

Ok one down one to go... Since I can't find it on any threads. The oil sending unit part numbers are a Wells PS4 or a BWD S334. The BWD is sold at Orielly's and Advance Auto. Auto Zone sells the Wells. (not recommended.)

After 2 Wells PS4s, and a lot of head scratching. Both of the PS4's were bad from the factory. That was where I was having problems. The resistance was all goofed up, not even near correct from their website.

I went down to Advance and got a BWD S334 and looks like that did it. I tested it with air pressure. From 0 to 100 psi I got pretty much full range of the gauge. (engine has oil pan off at the moment). The way the sending unit is designed, if you have less than about 8psi (BWD says 4-8) the gauge will drop to the bottom. Just an fyi.

Onto the temperature gauge. I tested 2 sending units and they seem to be correct. I grounded the gauge and left it open. It won't drop below 1/3rd scale. I am guessing the needle is sticking and not sure what to lube it with, even if it is possible to get to it. Best I am thinking is a small amount of graphite.

Oh by the way... I have a 460, it has the distributor in the front, and the sending unit is in the center of the block, on the top behind the intake manifold. What a fun place to get to. Plenty of room for a larger sending unit, but you may have to pull the throttle body to reach it. Mine was not too bad because I already had the throttle body off. Here is a pic for the interested.


460 oil sending unit

 

If the temp gauge appears to be stuck at the 1/3 place, I would take the cluster's clear cover off and carefully physically move it just below the low temp side. Unplug the temp sending wire from sender, then turn on ignition but don't have to start engine and watch what that gauge does. It should stay right around the low temp side.

Now if it pops up to where it usually sits cold, it may be the needle was moved(my 89 F250 temp guage has moved on me, but too low) on the gauge pivot.

If it stays down proper, then ground the temp sending wire, the gauge should peg to full hot side, release grounded wire and it should drop back to low side. By grounding and ungrounding the temp gauge wire, you should be able to get full scale both ways. If it sticks in one spot, then gauge is problem, best to find a good one than trying to clean the old one.

Inside the gauges is silicone oil or equ and washing that out will cause the gauge to not be dampened in movement. This is for most of the 87 to 96/7 Ford trucks with the air core meter movement.

 

Yea I grounded and opened the wire and it will go to the top of the scale but not below 1/3rd. When I get a chance next, I will take the cover off and check the needle like you mentioned. 12 hour days for the next few.

I am not sure if I move it by hand if it would stick again in the future.

How easy it is to swap a gauge only, not the whole cluster, just the gauge pair??

 

The gauges just press into the cluster housing. Once the lens is off you can carefully pry it out with a pocket screwdriver.