Can A Speedometer Drain a Car Battery?

battery drain in speedometerI have a Pontiac Grand Am with 2.2 4 cylinder engine.  It was involved in a front end crash, no air bag deployment and only cosmetic damage to bumper assembly and driver’s side headlight.  Repairs completed, but now I have a parasitic battery drain.  The battery and the alternator have been tested both in and out of the car separately.  With engine running battery voltage is 14.4.

Using a mulitmeter set to 10A, I have a drain of 0.65+.  If I remove both R/H and L/H BEC IP fuses the drain drops to 0.0.  Moving inside to the IP fuse blocks I get the following drains…..(well I seem to have misplaced the actual numbers, but) the fuses:  BFC Batt appx 0.30  also  IPC/HVAC Batt appx 0.30 and (on the passenger side BEC)  the fuse for  Radio Batt  appx 0.05.  These 3 fuses are the only ones showing amperage with the engine and key off.

I left the two BEC IP fuses out over night and had no additional drop in voltage of the battery.  It would not start the car but I attribute that to only 10.42 volts in the battery after all the testing yesterday.  However, I noticed an entirely different issue immediately after trying to start the car … battery acid was bubbling out of the battery???  I let the car crank for a period of time to see if it would catch….. it turned over very slowly at first then picked up but not enough to actually start.

My question at this point is…. now what?  How do i further isolate the drain and hopefully fix it?

Thanks in advance for your help.



Hey there JC,

.050 is max amp drain you are really allowed without draining a battery down over night, you have more than that.

We feel you have done a great job in tracing down this drain and have pinpointed the culprit, something with your instrument panel is staying energized.

Now, what to do about it, we feel that if we were in your situation in our shop we would either call a mobile speedometer repair company (which we have in Houston) or would buy a used instrument panel cluster from a junk yard and try that, which might actually be cheaper in the long run rather than having yours repaired.

Please share this with your friends

Austin Davis

1 Comment on "Can A Speedometer Drain a Car Battery?"

Trackback | Comments RSS Feed

  1. CGS intake says:

    Did you try replacing the battery? Maybe it’s not of the original manufacturer and its really just defective.

Got Something to Say?